MINISTRY OF EDUCATION
AND TRAINING
VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY
GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY
---------------------------
PHAM CONG NGUYEN
STUDY ON ENHANCEMENT OF TECHNICAL
CHARACTERISTICS FOR SOME COMPOSITE RUBBERS
WITH NANO ADDITIVE
Major: Organic chemistry
Code: 9.44.01.14
SUMMARY OF CHEMICAL DOCTORAL THESIS
Hanoi - 2019
The work was completed at: Academy of Science and Technology-
Vietnamese Academy of Science and Technology
Science instructor: Pro.Doc. Do Quang Khang
Reviewer 1: …
Reviewer 2: …
Reviewer 3: ….
The thesis will be protected before the doctoral dissertation thesis, meeting
at the Academy of Science and Technology - Vietnam Academy of
Science and Technology at ... hour ... ', date ... month ... 2018
The thesis can be found at:
- Library of the Academy of Science and Technology
- National Library of Vietnam
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A: Overview of the thesis
1. Problem statement Polymer nanocomposite material in general and rubber nanocomposite
in particular are particularly interested in research and development in the time to come because they have many superior properties superiority.
In rubber applications, reinforcement mostly used in orrder to create better quality products and reduce costs (active fillers). Traditional reinforcement in the rubber industry such as black coal, silica, clay powder... These enforcements were predominantly micro-sized at lower costs, so they are often referred to as fillers (active or inert fillers). Rubbers are reinforced with these materials are called composite rubbers.
Different from rubber composite, rubber nanocomposite was reinforced with nanometer-sized fillers (their size has one of three dimensions below 100nm), nanocomposite rubbers were created by different techniques, such as mixing in a melted state, mixing in solution, mixing in latex state followed by method of coagulation and polymerisation around filler particles. Compared to rubber reinforced with micro fillers, rubbber reinforced with nano fillers has better stiffness, modular, anti-ageing and airproof property. For each type of filler, besides advantages, there are always disadvantages. Therefore, in order to promote advantages and limit disadvantages of each type of filler, recently, some researches have combined two type of fillers together [1,3] but not much. Realizing that the research direction of combining nano-additives with black coal reinforced for rubber materials is a new direction today, because the number of published works is still small and it is unclear the influence when combining black coal with nano clay, nanosilica and carbon nanotubes. Stemming from that reason, the thesis is aimed at: “Study on enhancement of technical characteristics for some composite rubbers with nano additive” as the subject of research. 2. Objectives of research and its content
The objective of the research is to evaluate combination ability of nano additive with carbon black reinforced for rubber and rubber blend. - Create rubber nanocomposite materials with a high quality, solvent durability and sustainability in the naturally humid environment. The content of the research: - Study on denaturing nanoclay, carbon nanotubes, nanosilica surface with different agents, - Study on manufaturing and evaluating the property of rubber nanocomposite based on the blend of natural rubber (NR)/rubber butadien acrylonitril (NBR); natural rubber (NR)/Rubber clopren (CR) reinforced with nano additive, - Study on combining nano reinforced material with carbon black using in four type of substrates: natural rubber, blend natural rubber (NR)/rubber
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butadien acrylonitril (NBR); natural rubber (NR)/Rubber clopren (CR) and blend rubber butadiene acrylonitrile (NBR)/polyvinyl chlorite (PVC), - Study on combining nanosilica, nanoclay and carbon black materials with each other in the substrate of blend rubber NR/CR.
3. Contributions of research - Denatured, organized nanoclay with a mixture of surfactants (DTAB; BTAB; CTAB with molar ratio was 30:5:65). Obtained organic clay with properties: 21,3% organic content; distance d100 = 1,86nm; swells in organic solvent (axetone, xylene: 16; 23ml). - Optimal CB content for rubber blend NBR/PVC (70/30) was 40 pkl. At this
content, the materials had tensile strength increased by 47,1% compare to
sample that had no containing CB. With higher CB content (50 pkl), carbon
black particles tend to agglomerate making the tight structure of the material
is broken, resulting in reduced material mechanical properties.
- Suitable CNT content in order to combine replacing CB was 1 pkl. With
CB/CNT content (39/1), rubber blend materials had structure tighter.
Mechanical, thermal durability and thermal conductivity properties of rubber
blend materials NBR/PVC were incrseased.
- Rubber blend nanocomposite materials NBR/PVC/39CB/1CNT had high
mechanical-physical-technical properties can be satisfactory in order to
create technical rubber products, especially abrasion resistance and great
friction rubber products.
- Suitable carbon black content in order to reinforce for natural rubber, blend
NR/CR and NR/NBR was in the range of 25-30pkl. Combined nanosilica
content for these blends were quite similar 5pkl. So, in order to reinforce for
NR and blends with CR and NBR were 25pkl carbon black and 5pkl
Nanosilica. At this content, breaked tensile strength increased about 11% (for
NR), 18% for blend of NR/CR and 16% for blend of NR/NBR.
- Suitable carbon black content in order to reinforce for rubber blend
materials based on NBR/PVC were about 40pkl (compare to 100% rubber
blend), significantly higher compare to material system from natural rubber
and blend of NR with CR and NBR (only form 25-30pkl). At combining
ratio of carbon black/CNT (39/1 pkl) giving tensile strength of material
increase11%, increasing decomposition starting temperature as well as
environmental durability.
4. The thesis structure The research includes 136 pages with 32 tables, 93 figures, 133 references.
The thesis structure: Introduction 2 pages, Chapter 1: Overview 40 pages, Chapter 2: Materials and research methodology 10 pages, Chapter 3: Results and discussion 67 pages, Conclusion 2 pages, The publications relating to the thesis 1 page, References 12 pages.
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B. Content of the thesis Introduction
The introduction mentions the scientific and practical meaning. Then set targets and research content of the thesis. Chapter 1: Overview
The overview synthesizes materials inside and outside the country relating to the topic of the thesis such as: - Rubber materials, rubber blend, nanocomposite rubber materials with its classification, its specific advantages and disadvantages. - Nano additives (carbon, silica, nanoclay) and methods of surface denaturation, which also indicate that the denaturation method by using mixture of surfactant created organic clay with high quality. - The application of nano additives and the combination of black coal in nanocomposite rubber technology. The combination of black coal with nanomaterials (mix 01 or 02 nanomaterials) is the target of the thesis.
Chapter 2: Materials and research methods
2.1. Raw materials and chemicals - Carbon nanotubes multi wall: Baytubes - Bayer (Germany), 95% purity, - Bis- (3-trietoxysilylpropyl) tetrasunfide (Si 69.TESPT), China: the
transparent yellow liquid, fat-soluble and aromatic as alcohol, ether, keton.
Boiling point: 250°C, density: 1.08.
- Polyetylenglicol: PEG 6000 (BDH Chemicals Ltd company Poole-UK), the
melting temperature of 61°C.
- Polyvinylclorua: 710 SG Vietnam, a white powder, size: 20-150
micrometers, specific mass: 0.46- 0.48g/cm3.
- D01: refined tung-tree oil, yellow liquid, the proportion (at 20°C): 0.920-
0.945g/cm3.
- Cetyl trimetylamoni bromua (CTAB): Merck (Germany), M =
364.46g/mol, purity: 97%.
- Pure AlCl3: Merck (Germany).
- Natural Rubber (NR): SVR- 3L, Viet Trung rubber company, Quang Binh.
- Nitrile rubber (NBR): Kosyn- KNB35, Korea, containing acrylonitril 34%. - Clopren Rubber (CR): Baypren® 110 MV 49 ± 5, Lanxess - Vulcanizing additives include:
+ Sulfur, Sae Kwang Chemical Ind firm. Co. Ltd. (South Korea)
+ Zinc Oxide Zincollied; Stearic acid PT. Orindo Fine Chemical (Indonesia);
Accelerators DM (Dibenzothiazolil disunfit), Accelerators D (N, N-diphenyl
guanidine), Aging antioxidants D (Phenyl β-naphtylamin) of China
- Other chemicals: Hydrochloric acid, toluene, KOH, iso-octane, ethanol
96%, acid acetic, DMF, petroleum ether, SOCl2, H2O2, NH3, tetrahydrofuran
(THF), chloroform (CHCl3), CaCl2, acetone, petroleum ether of China.
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2.2. Process of denaturing CNT surface and manufacturing rubber nanocomposite material reinforced-CNT 2.2.1. Denaturing CNT surface by Fischer esterification reaction
The residual metal is removed from CNT by being soaked with special HCl and stirred for 2 hours at 50°C under a normal condition, washed several times with distilled water until pH = 7, dried for 12 hours, signed p-CNT. Disperse 0.3g p-CNT in 25ml mixture of NH4OH and H2O2 (1:1). Stir the mixture for 5 hours at 80°C under normal pressure. Mixed product is filtered by a PTFE membrane (capillary size: 0.2mic), washed with distilled water in neutral environment and cleaned by acetone several times. The denatured product (CNT-COOH) is dried for 48 hours at 80°C. - Chlorinated CNT
Put 0.5gam CNT-COOH into a flask 100ml with 20ml SOCl2 and 10ml DMF available inside, and stir under a normal pressure for 24 hours at 70°C. By the end of the reaction will be a dark brown mixture CNT-COCl, filter and wash with THF and dry at normal temperature. - Synthesis of CNT-PEG
Melt 1g PEG at 90°C, then put into a flask containing 0,1g CNT-COCl, stir for 10 minutes, then add the 40ml mixture of benzene/THF (3:1). Conduct the reaction at 80°C in 40 hours. When the reaction ends, put the mixed product in ultrasonic vibration for 30 minutes at 60°C, speed 3000rpm, then filter it through the PTFE membrane, the mixed black solid is washed with acetone and petroleum ether 3 times, dry at 90°C for 12 hours. 2.2.2. Alkylize CNT surface
Put 0.2g CNT and 0.5g PVC into a 3-neck flask with 30ml anhydrous CHCl3 available inside, the flask is connected to a canister of anhydrous CaCl2 and another pipe embedded in NaOH liquid 10% to remove HCl released during the reaction. Add 0.5 g AlCl3, and mix in nitrogen environment at 60°C for 30 hours. After cooling the mixture down to the normal temperature, the CNT-PVC product is stirred in ultrasonic vibration in the tetrahydrofuran solvent (THF) for 10 minutes, filtered and washed several times with petroleum ether and acetone, dried at 60°C in 10 hours. 2.2.3. Denatured nanosilica by TESPT
The denatured nanosilica process with bis-(3-trietoxysilylpropyl) tetrasulphite (TESPT) was carried out in 96% ethanol solution according to the procedure shown in figure 2.1. The reactions carried out in solution with pH = 4÷5 contain 0.5; 1; 2; 4% silane by weight. Reaction time is 1, 2, 4 and 8 hours respectively. The temperature of the reaction was surveyed at 200C, 250C 300C, 350C, 400C, 500C and 700C, respectively. Nanosilica/solvent ratio is 1/4. The mixture is stirred and remains constant throughout the reaction process. Mixture after the reaction is filtered and polymerized at 500C for 30
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minutes, then maintained at 1000C for 1 hour. The product was obtained, dried at 1000C at atmospheric pressure for 2 hours. 2.2.4. Denatured clay The process of denatured clay such as the following: Clay has not yet been denatured in 50ml distilled water at a temperature usually obtained mixture (1). Take 100ml of distilled water into a 250ml glass of heat to 800C, stir with a speed of 700rpm. Then slowly pour (1) into. Obtain mixture (2), Keep mixture (2) stable at 800C for 2 hours. Take 50ml of distilled water to heat the cup to 800C. Add surfactant and stir to dissolve. Collect mixture (3) Pour slowly (3) into (2) and keep at 800C for 4 hours. Take clay that has denatured to pour into the order printing filter funnel to filter the precipitate. Wash with hot water 80-900C until Br- ends, titration with AgNO3 0.1N. Drying and grinding. 2.2.5. Method of creating a rubber nanocomposite 2.2.5.1. Natural rubber/nano additive 2.2.5.2. Rubber blend based on NR 2.2.5.3. Rubber blend sử dụng carbon black phối hợp with nano additive
Table 2.3: Rubber compositing application, blended rubber with nano coal
No Ingredients Content (volume section) 1 Rubber (Rubber blend) 100 2 D01 (TH1) 2(1) 3 Paraffin 2.0 4 Zinc oxide 4.5 5 Aging antioxidants A 0.6 6 Aging antioxidants D 0.6 7 Stearic acid 1 8 Accelerators D 0.2 9 Accelerators DM 0.4 10 Cumaron 1.0 11 Sulfur 2.5 12 Nano additive 0-10 13 Black coal 0-50
2.2.5.4. Vulcanization Samples are made by saving the rubber materials in the mold with a sample size of 200 x 200 mm and a thickness of 2 mm. Pressing pressure: 6kg/cm2; Vulcanization time: 20-25 minutes; Vulcanizing temperature: 145oC. Vulcanizing process is performed on hydraulic press (20T) TOYOSEIKI experiment (Japan). 2.2.6. Research methods (1) Infrared (IR) method on FTS-6000 P (Biorad, USA). (2) Raman spectrum method with HR LabRAM 800 (France). (3) UV-vis spectra on the SP3000 nano machine (Japan).
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(4) Setaram machine's thermal weight analysis method (France), the heating speed is 10oC/min in the air environment, the study temperature range is from 25oC to 800oC. (5) X-ray diffraction spectroscopy on Siemens D5005 at the Department of Solid Physics - Faculty of Physics - University of Natural Sciences (Hanoi National University). The sample is crushed into a fine powder. The radiation source is CuK ( = 0.154 nm), the voltage of 40 KV, the intensity of 30 mA, the scanning speed of 0.020/2s from angle 2 is equal to 00 ÷ 100. (6) Research method using emission field scanning electron microscope (FESEM) implemented on S-4800 machine of Hitachi (Japan). (7) Method of studying morphological structure on transmission electron microscopy (TEM) on Jeol 1010 (Japan) machine. (8) Determination of particle size The size and distribution of nanoparticles before and after denaturation were determined by laser scattering method on Horiba Partica LA-950 device (USA) at Institute of Materials Chemistry, Military Science and Technology Institute. (9) Methods of determining the physical and mechanical properties of materials. Chapter 3: RESULTS AND DISCUSSION
3.1.1. Modified carbon nanotubes additive
3.1.1.1. CNT denaturation by polyvinylcloride
Dispersion results in organic solvents:
Figure 3.2: Dispersion of CNT (a) and CNT-g-PVC (b) in THF
After alkylation, on the infrared spectrum (IR) of CNT-g-PVC (figure
3.3b) compare to the IR spectrum of CNT (figure 3.3a), the absorption peaks
appear at 3048cm-1, 2914cm-1 corresponding to the valence oscillation of the -
CH, -CH2 group and absorption peak at 1437cm-1 corresponding to the strain
variation of the -CH2 group in the -CH-CH2- group. In addition, an absorption
peak at 618cm-1 is found with the valence oscillation of the C-Cl bond.
Figure morphological structure of materials: The morphological
figure structure of CNT not denatured and CNT-g-PVC is studied by FE-
SEM method, results are shown in figure 3.5 below:
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Figure 3.5: FE-SEM image of the surface of CNT (a) and CNT-g-PVC (b)
After oxidation, the structure is quite uniform with less shrinkage,
diameter of CNT-g-PVC increase significantly up to 23.6 - 29.1nm (CNT
diameter before joining PVC chain only 9.26 to 15.1nm).
3.1.1.2. Modifying CNT surface with PEG
CNT surface modification diagram by PEG is described in Figure 3.9:
Figure 3.9: Diagram of denatured CNT surface by Fischer esterification reaction On the spectrum of CNT-(CO)-PEG (Figure 3.10), there is a peak of 3264cm-1 characteristic for oscillation of OH group at the end of circuit CNT-COO-(CH2-CH2)n-OH, pic 3624cm-1 and 1668cm-1 denotes the signal of the NH group, the peak 1716cm-1 is the strong signal of the group (C = O) ester. The IR spectrum of CNT-(CO)-PEG also appears 1038cm-1 pic assigned to the CO group in PEG, the two peaks 2836 cm-1 and 3019cm-1 characterize the symmetric oscillation and antisymmetry of the joint C-H link in PEG. + Content group -(CO)-PEG and group -(CO)-TESPT paired on CNT: Content group -(CO)-PEG and group -(CO)-TESPT grafted onto CNT surface is also determined by the method of distribution Heat buildup (TGA). Results analysis is obtained, shown in Table 3.4.
Table 3.4: Results of TGA analysis of CNT-(CO)-PEG and CNT-(CO)-TESPT
Sample
Starting
decomposition
temperature
Strong
decomposition
temperature
most 1, oC
Strong
decomposition
temperature
most 2, oC
Mass loss
to 750oC,
(%)
CNT 4900C 629.77 0C - 13.50%
CNT-(CO)-PEG 4050C 449.150C 619.110C 36.63%
The thermal decomposition of CNT-(CO)-PEG starts at about 4050C and reaches a peak at 449.150C, extending until 619.110C, then the speed decreases until it reaches 7500C no longer losing weight, at this level of mass loss is about 36.63%, it is possible to roughly calculate the content of CO-PEG functional group attached to the surface of CNT corresponding to
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23.13%. From the results of thermal analysis of the weight of CNT-(CO)-TESPT sample, this material began to decompose at about 3990C and occurred strongly at 446.63oC lasting until 684.26oC. Starting decomposition temperature low as well as maximum first decomposition is low of organic groups attached to the surface of CNT as well as the poorly structured components of CNT begin to decay. The corresponding decomposition of the amino group and separation of sulfur atoms according to the reaction [8]:
(CNT-COO)3Si(CH2)3S4(CH2)3Si(OH)3 Ct0
(CNT-COO)3Si(CH2)3S-H Next is the decomposition process of CNT and its heat-stable
components. The process lasts until about 750oC, the volume does not change anymore, at this temperature the volume loss of the whole sample is 23.31%, so that can calculate the content of the preliminary group -(CO)-TESPT grafting on CNT surface is 9.81%. Comment: From the research results obtained shows that: - By alkyl reaction Fridel Craft has assembled PVC on the surface CNT with content PVC composite is about 23.0%. - By the surface reaction of Fischer esterification CNT (oxidized) by TESPT or PEG, 23.13% of group (-CO)-PEG and 9.81% -(CO)-TESPT on CNT surface. 3.1.2. Denatured nano additivesilica 3.1.2.1. Determine the optimal concentration of silane
The infrared spectrum of Bis- (3-trietoxysilylpropyl) tetrasulphite (TESPT) is shown in figure 3.2.
Figure 3.11: FT-IR of Bis-(3-trietoxysilylpropyl) tetrasulphite (TESPT)
From figure 3.11, it was found that, in the range of 4000 - 400cm-1, TESPT has a number of characteristic absorption bands, namely: in the wave number of 3000 - 2800cm-1, there is a fluctuation of the etoxy group, the number of waves from 1200-1000cm-1 asymmetrical stretching oscillations of C-O-Si, 1000 - 600cm-1 with stretching oscillation of C - C and oscillating symmetry of C - O - Si, under 500cm-1 with knives Dynamic deformation of C - O - Si. The oscillations of TESPT at 2990cm-1 and 1395cm-1 are asymmetric and symmetrical strain fluctuations of the methyl group (-CH3) in ethoxy. Pic 2883cm-1 is the asymmetric oscillation of C-H in CH3. Pic 1445 and 1395cm-1 are respectively asymmetric deformations of C - H in methylene (CH2) and methyl groups.
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Figure 3.12: FT-IR spectrum of
nanosilica
Figure 3.13: FT-IR spectrum of
nanosilica denatured TESPT at
different concentrations
- In the survey concentration range, the optimal concentration of silane in
order to denatured nanosilica is 2%.
- Continuing to rely on infrared spectra, comparing the intensity of peaks at
2930cm-1 and 2860cm-1, specific for C-H, the reaction time is 4 hours;
reaction temperature 300C;
- Size of silica particles after denatured:
Table 3.5: Particle size distribution of nanosilica has been denatured
% < 5 25 50 75 95
Size ( m) 0,05 0,11 0,15 0,28 0,88
Figure 3.21: Particle size distribution of nanosilica after denatured
The surface morphology of nanosilica particles before and after
denatured is described in figure 3.22.
a) Nanosilica b) Nanosilica denatured TESPT
Figure 3.22: TEM images of nanosilica particles and denatured by TESPT
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The TEM image in Figure 3.22 can be seen, after denaturing the nanosilica particles less agglomeration, leading to the reduction of particle aggregation size. The results are consistent with the results of particle size analysis in the above section. 3.1.3. Denatured nanoclay
The Nanoclay modified with HH1 (DTAB:BTAB:CTAB molar ratio of 30:5:65) is the most effective. There are basic distance characteristics d=18.6nm, highest organic matter content (21.3%), high degree of solids in solvents. 3.2. Research and manufacture rubber nanocomposite materials based on rubber, reinforced rubber blend with nano additives 3.2.1. Effect of nano content on the mechanical properties of materials 3.2.1.1. Effect of unmodified nano content on the tensile strength of the material
Nano (nanosilica (NS); carbon nanotubes (CNT); nanoclay (NC) are reinforced for the NR and rubber blend in different survey content from 1 to 10 pkl.
Figure 3.24: Tensile strength of
materials using non-denatured nano
Figure 3.25: Length of elongation of
nanomaterials not yet denatured
From the results in the table and the figures above, the content of
nano additives is suitable for each specific material background as follows:
- For NR substrate, the suitable reinforcement nanosilica content (NS) is
3pkl, resulting in maximum tensile strength and elongation when breaking.
- For rubber base blend NR/NBR nanosilica content reinforced at 7pkl,
resulting in tensile strength and elongation at maximum breaking.
- For rubber base blend NR/CR content of nanosilica with appropriate
reinforcement at 5pkl, resulting in tensile strength and elongation at
maximum breaking.
- For rubber base blend NR/NBR content of CNT reinforced at 4pkl,
resulting in tensile strength and elongation at maximum breaking.
- For rubber base blending NR/CR with appropriate reinforcement nanoclay
content at 5pkl, resulting in maximum tensile strength and elongation when
breaking 3.2.1.2. The effect of nano additive denatured on the mechanical properties of materials
Samples of materials are compared accordingly on the charts below:
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Figure 3.26: Comparison of tensile
strength of materials using denatured
and non-denatured nano
Figure 3.27: Comparison of elongation
at breakage of materials using
denatured and non-denatured nano
From figure 3.26 and figure 3.27 charts, the drag properties of superior denatured nano-materials compare to when not denatured 3.2.2. The influence of content nano on the figure structure of material 3.2.2.1. Figure structure of Thai NR material using nanosilica denatured and not denatured:
The NR of 3 pkl and 7 pkl nanosilica has not been and has been denatured by TESPT as shown in figure 3.30 and figure 3.31.
a. NR/3pkl nanosilica b. NR/3pkl nanosilica modified TESPT
Figure 3.30: Cutting surface FESEM image NR / NS 3pkl nanosilica
a. NR/7pkl nanosilica b. NR/7pkl nanosilica modified TESPT
Figure 3.31: Cutting surface FESEM image NR / 7 pkl nanosilica
From figure 3.30 and figure 3.31, it was found that, in all samples,
nanosilica particles dispersed in the NR substrate were mostly in sizes larger
than 100nm. In materials reinforced with non-denatured nanosilica (Figure
3.30a) nanosilica particles are dispersed more steadily, even with particles up
b a
a b
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to 1 m in diameter. Meanwhile, in reinforced materials 3pkl nanosilica
denatured by TESPT, nanosilica particles are more evenly dispersed and
have particles below 100nm (Figure 3.30b). In denatured material samples of
7pkl of non-denatured and denatured nanosilica, nanosilica particles are
poorly dispersed and there appear to be quite a large set of particles in both
cases (m-Figure 3.31).
3.2.2.5. Structure of figure thai model rubber blend materials NR/CR to
strengthen organic nanoclay:
On Figure 3.35 is a snapshot of the cut surface of some material
samples from them. From the FESEM image, when the low content nanoclay
(5pkl) dispersed nanoclay particles in rubber blend are quite uniform, the
particle size is quite small only from a few hundred nanometers.
Figure 3.35: FESEM photo cut surface of rubber materials NR/CR/nanoclay
(a) 5 pkl nanoclay; (b) 10 pkl nanoclay
The figures below are X-ray diffraction diagram of nanoclay and
denatured HH1 nanoclay material HH1.
Figure 3.37: X-ray diffraction scheme of
NR/CR containing 5pkl nanoclay HH1
Figure 3.38: Sample TEM image of NR /
CR containing 5pkl nanoclay
From the X-ray diffraction scheme in Figure 3.37, the reflection peak
(d001) of nanoclay after being dispersed into rubber blend NR/CR, the
distance of nanoclay increased strongly, approximately 4.08 nm (initial base
distance d001 = 1.86nm) with 2 angle = 2,2o. This result shows that the
structure of nanoclay layers has been changed and transformed into an
interlayer structure in rubber blends. This is also evidenced by TEM image in
Figure 3.38.
a b
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3.2.3. Effect of nano additive on thermal properties of materials
3.2.3.1. Effect of nanosilica on the thermal properties of NR material
50 100 150 200 250 300 350 400 450 500 550 600 650 700
0
20
40
60
80
100
Nhieät ñoä(o
C)
TG/% DTG/(%/phuùt)
Toån hao khoái löôïng:93,80%
358.18 0C, -11,15%/phuùt
-12
-10
-8
-6
-4
-2
0
100 200 300 400 500 600 700
0
20
40
60
80
100
Nhieät ñoä (o
C)
TG/%
363.450
C , -11.23%/phuùt
Toån hao khoái löôïng: -92.84%
-12
-10
-8
-6
-4
-2
0
DTG(%/phuùt)
Figure 3.40.a: TGA schema of
NR/3pkl nanosilica samples
Figure 3.40b: TGA schema of NR / 3 pkl
nanosilica denatured sample by TESPT
The mechanism of linking between nanosilica denatured by TESPT
and rubber substrate can be described as follows (figure 3.42):
Figure 3.41: Illustration of the reaction between NR and nanosilica denatured TESPT
This bonding makes the material structure more rigid than the
temperature and the highest decomposition temperature is higher than the
larger compare model using non-denatured nanosilica (up to 2,850C and
5,270C respectively). This is also the reason for the mechanical properties of
materials increasecao.
3.2.3.2. Effect of nanosilica on the thermal properties of rubber blend
materials
* Thermal properties of rubber blend NR/NBR reinforced nanosilica
* Thermal properties of rubber blend NR/CR system to strengthen nanosilica
* Thermal properties of rubber blend NR/CR system for nanoclay
reinforcement:
* Thermal properties of rubber blend NR/NBR reinforced CNT.
In general, when using nano additive denatured for natural rubber and
rubber blend substrates, the thermal properties of the fabric are positively
affected. When there is a nano additive surface in the rubber base material
that shields the impact of heat for rubber elements, it has increased the
stability and thermal durability for materials.
3.3 Research, manufacturing nanocomposite rubber materials based on
rubber blend carbon black reinforcement combined with nano additive
Silica Silica
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3.3.1. Combine nano silica and carbon black to reinforce natural rubber
3.3.1.1. The effect of content on black carbon on the mechanical properties of materials
When the carbon black content increases: tensile strength of the
material increase fast, the abrasion resistance resistance increases such as
only a certain limit of 25pkl and then begins to decrease again. The choice of
content carbon black is 25pkl used in order to conduct further surveys.
3.3.1.2. Effect of nanosilica on the physical properties of materials
The results of examining the effect of content nanosilica on the
mechanical properties of 25pkl carbon black NR materials are presented in
Table 3.16 below: Table 3.16: Effect of content nanosilica on the mechanical properties of NR material
containing 25pkl carbon black
Property
Content
nanosilica (pkl)
Tensile
strength
(MPa)
Elongation
tensile at break
(%)
Abrasion level
(cm3/1,61 km)
Stiffness
(Shore A)
0 21.40 643 0.985 56.0
3 22.94 663 0.948 57.1
5 23.72 655 0.944 58.3
7 19.81 632 0.973 58.8
Notice that the tensile strength, abrasion resistance, elongation and elongation of the material peaked at optimal nanosilica content when combined with carbon black for NR material is 5pkl. 3.3.1.3. Figure structure of the material
In order to evaluate the morphological structure of materials, we use scanning electron microscopy (SEM) in order to capture fracture surfaces of some typical material samples. Results are presented in figures 3.44, and figure 3.45 below:
Figure 3.44: Surface SEM image
fracturing NR/25pkl carbon black
material sample
Figure 3.45: Surface SEM image of
fractured material NR/25pkl carbon
black/5pkl nanosilica
Realizing that, in the natural rubber model, there are 25pkl carbon
black, carbon black filler is distributed relatively evenly on the surface of the
NR platform, but there is a convex surface. When 5pkl nanosilica is added to
the sample, the sample surface retains the regular distribution of such NR
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fillers as 25pkl carbon black reinforcement, but the surface is less convex.
This proves that with small content nanosilica still maintains the uniform
distribution of the components in the material block, the components in the
combination are better connected. Thus, the fractured surface of the material
is less convex, concave, indicating the figure structure of the tight material.
3.3.1.4. Effect of denatured process on thermal stability of materials
Table 3.17: Starting decomposition temperature and mass loss of quantitative materials
Sample
Starting
decomposition
temperature [oC]
The strongest
decomposition
temperature 1 [oC]
Weight loss
to 440 0C [%]
NR/25pkl carbon black 302.2 374.05 66,359
NR/25pkl carbon
black/5pkl nanosilica
303.6 374.07 65.829
NR/25pkl carbon
black/10pkl nanosilica
299.0 375.06 62.625
Realizing that the material's durability is a little bit higher when the content of nanosilica denatured is 5pkl (starting decomposition temperature increase of 1.4oC). When the nanosilica content is too high (10pkl) starting decomposition temperature of the material falls sharply (4oC reduction). This can be explained by the fact that the nanosilica content in the rubber component is too large, which leads to the formation of separate phases (such as the figure state structure indicated), reducing the tight structure of the material leading to The thermal stability of the material decreases. 3.3.1.5. Environmental stability of materials
The aging coefficient of the material is determined according to TCVN 2229-77 after testing in the air and salt water 10% at 70oC after 96h is shown in Table 3.18.
Table 3.18: Aging coefficient of the material after testing at 70oC after 96
hours of testing in air and 10% saline
Aging factor
Samples
In the air
(%)
10% salt water
(%)
NR/25pkl carbon black 0.80 0.80
NR/25pkl carbon black/5pkl nanosilica 0.86 0.85
Realizing that, when denatured with the NR reinforcement of 25pkl
carbon black with content nanosilica is appropriate (5pkl compare to NR) has
made the increase of environment for materials (aging coefficient in air and
salt water 10% both increases significantly). This can be explained by the
presence of nanosilica which makes the material more structured, preventing
the effect of oxygen in the air as well as other aggressive elements, making
the increase environmental durability for the material.
3.3.2. Combine nano additive silica, nanoclay and carbon black to enhance
the blend of natural rubber and rubber cloropren
16
In rubber processing technology, people use many types of
reinforcing fillers such as black carbon, silica, clay, dolomite, ... However, in
each specific rubber and additive system, the fillers have influence and
content Different optimizations. In this study, the nano additive used
includes: nanosilica (NS), carbon black (CB) and nanoclay (NC) as
reinforcement for the rubber blend system NR/CR (70/30).
3.3.2.1. The effect of content on black carbon on the mechanical properties of materials
Results of the survey are presented in figures 3.47 and 3.48 below.
Figure 3.47: Effect of CB content on
breaking strength and elongation at
breaking of materials
Figure 3.48: Effect of content of CB
on hardness and abrasion of
materials
Notice that, when content carbon black (CB) increasen, tensile strength of increaseand
material reaches maximum value at content carbon black is 30pkl. Own stiffness of
increasing material gradually with the increasecontent carbon black
The change of these values is because when the CB content is within the
optimal limit of CB particles forming its network, it also separates the large rubber
molecules in all directions to form a hydrocarbon network. Two interwoven networks,
hooked together to form a rubber structure - the filler continuously enhances the
mechanical properties of the material. From the above results, the combined carbon
black content is 30pkl selected to order in order to continue research.
3.3.2.2. The effect of nanoclay content replaces nanosilica to the mechanical
properties of the material
Table 3.19: The effect of nanoclay content replaces nanosilica to the
mechanical properties of the material Sample
(silica/clay)
Tensile strength
(MPa)
Elongation tensile
at break (%)
Stiffness
(Shore A)
Residual
extension (%)
SC0 (5/0) 22.79 608 61.4 14.0
SC1 (4/1) 23.14 632 61.8 13.8
SC2 (3/2) 24.56 653 62.0 13.2
SC5 (0/5) 22.85 607 63.2 12.0
Symbols of samples: SC0: NR/CR/5NS-30CB; SC1: NR/CR/4NS-30CB-1NC; SC2: NR/CR/3NS-30CB-2NC; SC5: NR/CR/30CB-5NC
17
Results on table 3.19 show that tensile strength and elongation when the
material's breakage reaches the maximum value when nanosilica content is replaced
with 2% nanoclay. Then, further increasecontent nanoclay replacement, these
properties of the material again reduced. Particularly stiffness of materials increases
and the residual extension is slow when the replacement content nanoclay increases.
This change in properties can be explained: on the one hand, nanoclay has better
reinforcement effect than compare to nanosilica. On the other hand, with content 2%
nanoclay in the material block can create nano additive resonance effects and thus,
tensile strength and elongation when breaking of the material is improved.
3.3.2.3. Effect of denatured process on thermal stability of materials
Thermal durability of materials is evaluated by thermal thermal analysis (TGA)
method. Results thermal analysis of models based on rubber blend NR/CR are shown
in figures and tables below:
Figure 3.50: TGA chart of material
sample NR/CR/5NS-30CB
Figure 3.51: TGA sample material chart
NR/CR/3NS-30CB-2NC
Realizing that the thermal stability of rubber blend material was significantly
improved when there was 30pkl of black coal through the decomposition start
temperature of the material increased sharply, from 280oC to 300oC.
When combining 2% nanosilica replacement with nanoclay, the thermal
stability of the material is also improved (the decomposition start temperature increases
by 6oC, the highest decomposition temperature increases by more than 3oC, percentage
of mass loss to 600oC of materials also decreased from 92.34% to 90.41%) Table 3.20.
Table 3.20: Analysis results of TGA sample rubber blend NR/CR with nano additives
Samples
Starting
decomposition
temperature [oC]
The strongest
decomposition
temperature 1 [oC]
The strongest
decomposition
temperature 2 [oC]
Weight
loss to
6000C [%]
NR/CR/5NS 280.0 347.3 443.1 91.92
NR/CR/5NS-30CB 300.0 347.4 447.8 92.34
NR/CR/3NS-30CB-2NC 306.0 350.7 446.5 90.41
3.3.2.5. Research Morphological structure of materials
Morphological structure of rubber blend material NR/CR/3NS-CB-2NC
nanocomposite is determined by methods such as emission field scanning
18
electron microscope (FESEM) and X-ray diffraction. Figure 3.53 below is a cut
surface FESEM image of the material sample.
Figure 3.52 Material cut surface FESEM image NR/CR/3NS-30CB-2NC nanocompozit
From FESEM images, nano-additives were dispersed in the rubber substrate quite evenly with a relatively small particle size below 100nm.
Results of X-ray diffraction analysis of modified nanoclay samples by mixture and sample NR/CR/3NS-30CB-2NC:
VNU-HN-SIEMENS D5005 - Mau Clay Na+ 38
File: Huynh-Toan-Giap-DHBK-Clay Na+ 38.raw - Type: 2Th/Th locked - Start: 0.400 ° - End: 10.000 ° - Step: 0.020 ° - Step time: 1.5 s - Temp.: 25.0 °C (Room) - Anode: Cu - Creation: 04/22/08 20:32:28
Lin
(C
ps)
0
1000
2000
3000
4000
5000
2-Theta - Scale
0.5 1 2 3 4 5 6 7 8 9 10
d=1
8.6
31
Figure 3.53: X-ray diffraction diagram of
nanoclay HH1
Figure 3.54: X-ray diffraction diagram of
NR / CR / 3NS-30CB-2NC
From the X-ray diffraction diagrams, the reflection peak (001) of
nanoclay appears at angle 2 = 5.2o with the base distance d = 1.86 nm
(Figure 3.53). With this base distance, the layers of the original nanoclay
remain in order. After being dispersed into rubber blend NR/CR, the base
distance of nanoclay increased to approximately 4.14 nm with the angle of
2 = 2.1o (Figure 3.54). This result shows that the structure the layers of
nanoclay have been changed and changed into interlayer structures in the
rubber base. Therefore, the physical and mechanical properties of the
material improved markedly.
3.3.3. Combined study of enhanced nano silica and black coal for blends
of natural rubber and nitrile butadiene rubber (NR/NBR)
3.3.3.1. Effect of black coal content on the mechanical properties of materials
The used black coal content surveyed in the range of 20pkl-35pkl
according to the result of the rubber content at 25pkl ratio is more
advantageous in terms of elongation when breaking and abrasion resistance.
19
Based on these results, the content of black coal of 25pkl is used to carry out
the next survey.
3.3.3.2. Effect of nanosilica on the physical properties of materials
The survey results of the effect of nanosilica content on the
mechanical properties of materials from NR with 25pkl of black coal are
presented in Table 3.23 below.
Table 3.23: Effect of nanosilica content on mechanical properties of NR material
containing 25pkl of black coal
Property
Content
nanosilica (pkl)
Tensile
strength
(MPa)
Elongation
tensile at
break (%)
Abrasion level
(cm3/1,61 km)
Stiffness
(Shore A)
3 23,12 670 0,925 60,2
5 24,82 668 0,914 63,5
7 21,81 653 0,943 68,8
Thus, similar to the survey of NR/CB system of NR/NBR (80/20) blend
with 25pklCB content in gravel. The optimal nanosilica content is also 5pkl.
3.3.3.3. Study the morphological structure of materials
To evaluate the morphological structure of the material, a scanning
electron microscope (SEM) was used to capture the fractured surface of a
number of typical material samples. The results are shown in the pictures below:
Figure 3.55: Surface SEM image
destroying NR/NBR/25pkl CB material
sample
Figure 3.56: Surface SEM image
destroying material sample
NR/NBR/25pkl CB/5pkl NS
Realizing that, in the NR / NBR blend with 25pkl of black coal, the
black coal filler is distributed relatively evenly on the surface of the
substrate, but compared to the sample with 5pkl nanosilica, the surface is
more smooth and uniform. With the content of 5pkl nanosilica has strong
effect on the morphological structure of the material NR/NBR blend in a
positive direction, thus increasing the mechanical properties of the material.
3.3.3.4. Effect of the denaturing process on the thermal stability of the material
The thermal stability of the material is assessed through thermal
decomposition by thermal weight analysis (TGA). Research results are
presented in table 3.24 below.
20
Table 3.24: Thermal stability of rubber NR/NBR/CB with and without nanosilica
Sample
Starting
decomposition
temperature [oC]
The strongest
decomposition
temperature 1 [oC]
Weight loss
to 4400C [%]
NR/NBR/25pklCB 320.2 390.8 65.39
NR/NBR/25pklCB/5pkl NS 334.6 396.7 61.15
Realizing that the thermal stability of the material increases when the
denatured nanosilica content is 5pkl (decomposition start temperature
increases by 14.4oC, the highest decomposition temperature increases ~6oC).
3.3.4. Study on the combination of CNT and black coal additive nanoparticles for blending materials of nitrile butadiene rubber and polyvinylchloride (NBR/PVC) 3.3.4.1. Effect of black coal content on the mechanical properties of materials
The survey results of the effect of CB content on the mechanical properties of
rubber blend NBR / PVC (70/30) are shown in the figures 3.58 and 3.59 below:
8
11
14
17
20
23
26
0 10 20 25 30 40 50
Hàm lượng CB (pkl)
Độ
bề
n k
éo
đứ
t (M
Pa
)
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Độ
mà
i mò
n (
cm
3/1
,61
km
)
Độ bền kéo đứt
Độ mài mòn
150
200
250
300
350
400
450
0 10 20 25 30 40 50
Hàm lượng CB (pkl)
Độ
dã
n d
ài k
hi đ
ứt
(%)
40
50
60
70
80
90
100
Độ
cứ
ng
(S
ho
re A
)
Độ dãn dài khi đứt
Độ cứng
Figure 3.58: Effect of CB content on
breaking strength and abrasion of materials Figure 3.59: Effect of CB content on hardness
and elongation at breaking of material
Realizing that, when the black coal content (CB) increases, the tensile
strength of the material increases and the abrasion decreases. At the CB
content of 40 pkl, the tensile strength reaches the maximum value and the
abrasion reaches the minimum value.
3.3.4.2. Effect of CNT content replacing black coal (CB) on mechanical properties of materials
Table 3.26: Effect of CNT content replacing CB to mechanical properties of materials
Sample Tensile strength (MPa)
Elongation tensile at break (%)
Stiffness
(Shore A) Abrasion level
(cm3/1,61 km)
NBR/PVC/40CB 24,28 328 86,0 0,261
NBR/PVC/39.5CB/0.5CNT 25,19 342 86,3 0,243
NBR/PVC/39.0CB/1.0CNT 27,01 353 87,0 0,226
NBR/PVC/38.5CB/1.5CNT 25,33 338 87,4 0,229
The results in table 3.26 show that the tensile strength, elongation at breaking and abrasion resistance of the material reach maximum at 1pkl CNT content. When the CNT content continues to increase (greater than 1 pkl) these properties of the material tend to decrease.
21
3.3.4.3. Study the morphological structure of materials ơ
From FESEM images, the NBR/PVC sample contains 25pkl CB,
carbon black particles are distributed relatively evenly on the surface of the
rubber base. However, on the fractured surface of the material still has
concave convex phenomenon. When the content carbon black increase reaches
40pkl, the carbon black particles are more evenly distributed on the broken
surface, the broken surface of the material is quite smooth, so the figure
structure of the material is tighter. When replacing 1pkl CB with 1pkl CNT,
on the broken surface of the material, the carbon black particles disperse and
interact with the rubber substrate better. Therefore, with 1pkl CNT replacing
CB has significantly improved the mechanical properties of materials.
3.3.4.4. Mechanical thermodynamic properties (DMA)
Thermodynamic analysis allows to determine the temperature of Tg
vitrification of polymers, storage modules (E '), loss module (E' '). The effect
of temperature on E 'storage module of samples at 1Hz frequency is shown in
Figure 3.62. The E value indicates the ability to disperse energy due to
molecular motion, so E 'represents the hardness of the material. Modul E
'depends on 3 reasons: density density, content of dispersed fillers, dispersed
particle size.
Figure 3.61: Storage module diagram
of the material
Figure 3.62: Melt delta diagram
of the material
Figure 3.60: Surface
FESEM image
fracturing samples
of NBR / PVC
materials containing
reinforced fillers
(a)-25CB;
(b)-40CB;
(c)-50CB
(d)-39CB/1CNT
22
The results in Figure 3.61 show that the rubber blend samples have large
storage modules at low temperatures, then plummet in transition areas. For 2
samples of rubber blend with added reinforcement filler, module E' of materials
increased significantly, especially samples containing 1pkl CNT. In the low
temperature zone, these two samples have different values of storage modules, this
difference is evident in high temperature areas. This proves that CNT has reduced
the mobility of molecules in materials at high temperatures.
The results in Figure 3.62 show that the rubber blend
NBR/PVC(70/30) is compatible with each other (tan delta curve only appears
a sharp peak with Tg = 22.74oC in the middle of the high chemical
temperature of the Su NBR (-230C) and PVC (+600C)). Two rubber blend
samples had added reinforcement filler, tan delta peak intensity and reduced
glass temperature (due to increased storage module E').
3.3.4.5. Thermal properties of materials
The thermal stability of the material is assessed by weight thermal
analysis (TGA) method. The results of TGA thermal analysis of samples
based on blended NBR/PVC rubber are shown in Table 3.27 below.
Table 3.27: Results of TGA analysis of blended NBR/PVC rubber
Sample
Starting
decomposition
temperature
[oC]
The strongest
decomposition
temperature 1
[oC]
The strongest
decomposition
temperature 2
[oC]
Weight
loss to
3300C
[%]
NBR/PVC 192.3 266.3 430.1 17.53
NBR/PVC/40CB 196.5 267.3 436.7 13.41
NBR/PVC/39CB/1CNT 206.3 268.3 434.4 13.05
3.3.4.6. Thermal conductivity
To study the effect of CB and CNT on the thermal conductivity of the
material, the thermal conductivity of the samples is determined on the THB
500 device of Linseis. The results of thermal conductivity of samples based
on NBR / PVC blend rubber are presented in Figure 3.66.
0.4
0.5
0.6
0.7
0.8
20 30 40 50 60 70
Nhiệt độ (oC)
Độ
dẫn
nh
iệt
(W/m
*K)
NBR/PVC
NBR/PVC/40CB
NBR/PVC/39CB/1CNT
Figure 3.66: Thermal conductivity of rubber blend samples by temperature
23
The above results show that the thermal conductivity of materials
increases when there are CB and CNT. At a temperature of 30oC, with 40pkl
CB, the thermal conductivity of the material increased slightly from 0.509 to
0.574 W/mK, while only 1 pkl of combined CNT replaced the thermal
conductivity CB of the material increased sharply (to 0.691 W/mK).
When raising the temperature, the thermal conductivity of rubber
blend samples increased. For blends that do not contain reinforcement fillers,
the thermal conductivity does not increase significantly. Meanwhile, blends
contained 39CB/1CNT with the highest thermal conductivity. It is the ability
to increase high thermal conductivity when increasing the temperature so
blended rubber products based on NBR/PVC with CB and CNT can reduce
endogenous heat during operation.
CONCLUSION
1. The proper process for denaturing some nano additives is as follows:
- For nanoclay: Ratio of HH1: DTAB denatured mixture: BTAB: CTAB is
30: 5: 65 according to the molar portion. The properties of organic clay HH1
has a basic distance d = 1.86nm; organic content of organic clay in HH1 =
21.3%;
- For nanosilica: Suitable conditions for silaneization of nanosilica surface
by TESPT: concentration of 2% silan solution in ethanol, 4h treatment time
and reaction temperature of 300C. Nanosilica surface silane coating has a
content of 3.07%.
- For carbon nanotubes: By alkylation of Fridel Craft, it is possible to
assemble PVC onto the surface of CNT with compound PVC content of
about 23.0%. With the Fischer esterification reaction, the surface of CNT
(oxidized) by PEG was attached to 23.13% group ((CO)-PEG on CNT
surface.
2. With each type of nano additives reinforced for rubber, different rubber
blends will have different suitable content, specifically:
- The content of nanosilica suitable for reinforcement of NR is 3pkl, for
blending NR/NBR is 7pkl, NR/CR is 5pkl. At these levels, the physical and
mechanical properties of the material increased sharply. Especially tensile
strength increases from 17-25%, decomposition start temperature increases
from 12.5oC to 24.8oC (depending on the system)... When denatured with
silane coupling agent, these features continue Continue to increase from
5.1% to 20.5% (depending on each system).
- CNT content is suitable for reinforcing the NR/NBR blend is 4pkl.
Meanwhile, denatured additives CNT-g-PVC interact better with NR/NBR
substrate than CNT-g-PEG. Therefore, the NR/NBR/CNT-g-PVC sample has
24
mechanical properties and thermal stability higher than NR/NBR/CNT-g-
PEG samples.
- Appropriate content of nanoclay reinforced for NR/CR blend is 5pkl. In
this content, the obtained nanocomposite rubber material has a structure that
separates and overlaps the layer. The material has mechanical properties,
superior thermal and environmental resistance, compared to non-reinforced
NR/CR samples.
3. For each type of rubber base, rubber blends vary in the ratio of nano
additives combining different appropriate reinforced black coal. The content
of black coal is suitable for reinforcing natural rubber, blend of NR with CR
and blend of NR with NBR are in the range of 25pkl-30pkl (compared to
rubber). The content of nanosilica combined for these blends is also quite
similar to 5pkl. Meanwhile, the appropriate content of black coal to reinforce
rubber blend material on the basis of NBR/PVC (70/30) is about 40pkl
(compared to rubber blend). At the combined rate of black coal/CNT (39/1
pkl) for breaking strength, the decomposition start temperature as well as the
environmental durability of the material all increased.
4. When combining black coal reinforcement with nanosilica and nano
clay for rubber material blend NR/CR with the ratio of black
coal/nanosilica/nanoclay (30/3/2pkl) the physical and technical properties of
materials Very strong increase, especially tensile strength increased by
40.7%. Thus, when coordinating the reinforcement of nano-additives with
black coal, it is possible to increase the mechanical and technical features for
materials according to the effect of each type of additives used.
5. Reinforced rubber materials combine nano additives with black coal
with higher mechanical, physical and technical features than when
reinforcing each type separately. This is also a new research direction to
improve mechanical and technical features for rubber materials to
manufacture technical rubber products for economic and social development
because it can meet all two economic and technical requirements.
LIST OF SCIENCE WORKS RELATED TO THE
DISCLOSURE OF THESIS
1. Do Quang Khang, Luong Nhu Hai, Luu Duc Hung, Vuong Quoc Tuan, Do
Quang Minh, Pham Cong Nguyen. Research to improve physical properties
for materials based on natural rubber by black coal and nanosilica (2013).
Journal of Chemistry, 6BC, vol. 51, 244-248.
2. Luong Nhu Hai, Ho Thi Oanh, Pham Cong Nguyen, Le Thi Thuy Hang,
Do Quang Khang. Study on manufacturing and properties of basic rubber
nanocomposite materials blend of Nitrile andadiene natural rubber and
25
rubber with nano silica (2015), IXth National Solid and Scientific Materials
Conference - SPMS2015 - HCMC, 660-663.
3. Ngo Trinh Tung, Do Quang Khang, Luong Nhu Hai, Pham Cong Nguyen,
Le Thi Thuy Hang. Study on the effect of nano additives on the mechanical
properties of rubber blend NR/CR (2016), Chemical Journal, 6E1, volume
54, page 93-98.
4. Pham Cong Nguyen, Chu Anh Van, Ho Thi Oanh, Vuong Quoc Tuan,
Luong Nhu Hai, Do Quang Khang. Study on fabrication, morphological
structure, properties of NR/CR/silica nanocompozit materials (2016),
Chemistry Journal, 6E1, volume 54, 170-174.
5. Luong Nhu Hai, Pham Cong Nguyen, Ngo Trinh Tung, Luu Duc Hung,
Do Quang Khang. Study on fabrication, structure and properties of
nanocomposite rubber materials based on natural rubber, chloroprene
rubber for nanoclay reinforcement (2017). Journal of Chemistry, Episode 55
(1): 60-64.
6. Luong Nhu Hai, Pham Duy Suy, Nguyen Thi Ngoan, Nguyen Van Thuy,
Ngo Trinh Tung, Pham Cong Nguyen, Le Thi Thuy Hang, Ngo Ke The. On
the effect of carbon black, carbon nanotubes on properties of rubber blend
acrylonitrile butadiene rubber (NBR)/Polyvinyl chloride (PVC), (2017),
Vietnam Journal of Chemistry, Vol 55, No 5, 625-630,
7. Pham Cong Nguyen, Do Quang Minh, Do Trung Sy, Luu Duc Hung,
Vuong Quoc Tuan, Pham Quynh Trang, Tran Huu Huy, Do Quang Khang,
Research on manufacturing and properties of rubber nanocomposite
materials based on blends Nitrile butadiene rubber and polyvinylcloride
nanocarbon reinforcement (2018), Chemical Industry Journal, Vol. 8, 33-39.
8. Pham Cong Nguyen, Chu Anh Van, Luong Nhu Hai, Do Quang Minh,
Vuong Quoc Tuan, Tran Huu Huy, Le Hong Hai, Do Quang Khang. Some
results of study on modification of Carbon nanotube surface. Part 1:
Alkylation and oxidation of CNT surface (2018). Vietnam Journal of
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