10 th July 2013 - ALPlastics > Home school... · · 2013-07-31Polymerization of lactic acid ....

10th July 2013

Contents

o Introduction and definition

o Families

� Starch polymers

� Polylactic acid (PLA)

� Polyhydroxyalkanoates (PHA)

Biopolymers

� Polyhydroxyalkanoates (PHA)

� Biomonomers

� Hybrid polymers

o Market

o Biodegradability and compostability

o Conclusions

It’s interesting to note that biopolymers have been on the market since a

long time ago:

From renewable

resources:

• Cellulosic polymers

• Nylon 11

Biodegradable:

• Polycaprolactones

• EVOH

Biopolymers: a bit of history

• Nylon 11

• Natural gums

• EVOH

With the development of more economical technologies based on fossil

resources, biopolymers lost progressively importance.

In the 70s, after the first oil crisis, a new intense R&D activity was born

with the objective to create new classis of biopolymers from renewable

resources, for packaging, agriculture and single-use applications.

Materials, studied in these researches (TPS, PLA, PHA):

→ had the advantage to be

• produced from renewable resources

• compostable

→ but they

• had technological gaps in durable goods

• were very expensive


• were very expensive

In recent years, it can be seen a new progressive interest in these

polymers, in particular in the use of biomonomers to produce

traditional polymers.

The renewed interest in biopolymers is dictated by:

� the growing commitment in environmental issues

� the fear of possible crises linked to petroleum products.

An important aspect is that, today, waiting for biopolymers,

capable of replacing fossil,

In Japan was enacted a law providing for a 20% replacing of

fossil polymers by 2020.

is also accepted a their partial replacement


fossil polymers by 2020.

This has led to the development of:

→ hybrid polymers and

→ polymers with a partial content of natural resources

Biopolymers represent an area with great development

possibility, also because they combine high

�Technical potentialities and

�Environmental sustainability

From the point of view of raw materials and/or of

their end life recovery

Biopolymers

their end life recovery

According to “European Bioplastics Association”:

Biodegradable polymers with compostability

approved by EN 13432 standardBoth from renewable and not renewable resources

Polymers from renewable resources

Both biodegradable and not biodegradable

Na

tura

l o

rig

in

Fro

m c

rad

le

From renewable resourcesFrom renewable resources

biodegradable

Biopolymers

Foss

il o

rig

in

Not biodegradable Biodegradable

Fro

m c

rad

le

To grave

From fossil resourcesFrom fossil resources

biodegradable

1. Natural polymers that can be modified, but substantially

they remain unchanged (i.e. polymers from starch,

cellulosic polymers)

2. Through fermentation biomonomers, which are

subsequently polymerized (i.e. PLA)

Biopolymers

subsequently polymerized (i.e. PLA)

3. Biopolymers directly in microorganisms (i.e. PHA)

4. Polymers from biomonomers and fossil monomers

Harvesting Chemical corn’s treatment to

extract starch

(amylase and amylopectine)

There are strong

intermolecular bonds

between granules

Starch

Destructuration of starch and

ricombination to create new

blend

a)

Starch is a carbohydrate (polysaccharide) and it is present in

numerous plants (corn, potatoes, wheat). It’s composed of:

Starch

a)

b)

Amylase linear polysaccharide

Amylopectine branched polysaccharide

Structure and composition of starch’s particles varies with plant’s

type and ratio between amylase and amylopectine differs too.

Starch

K. Morawietz Bioplastics Conference 28/07/2007 Alessandria Italy

For this reason, starch polymers can be very different:

1. Polymer from pure starch (used like fillers);

2. Polymers from partially fermented starch;

3. Polymers from desctructured starch;

4. Polymers from modified starch (substitution of –OH groups

with ether or ester groups);

Starch

with ether or ester groups);

5. Blend of starch polymers and other polymers (polyesters,

PCL, CA, PVOH). Blends can vary their properties and can

be compared with flexible plastics like PE or rigid plastics

like PS.

For this reason it’s very difficult to do a comparison among

different grades and their properties.

Process. Units E EBM EBM/IM IM

Density g/cm3 1,28 1,28 1.28 1,4

MFR g/10’ 9 3 0.8

Young’s

modulusMPa 240 1100 1500 2050

Starch: properties

modulusMPa 240 1100 1500 2050

Tensile

strengthMPa 16 19 22 30

Elongation % 600 160 110 7

Melt point °C 136 146 147

�Low vapour barrier

� Sensitive to contact with H2O

�Good resistance to oils and fats

�Barrier properties depend on blend

formulation

Starch: properties

formulation

C.Bastioli EPF School, Gargnano maggio 2009

There is a great variability in

permeability properties: oxygen

barrier has an interval from PET

to HDPE

1. Polymers from pure starch

They can be processed on thermoplastic technology lines adding

plasticizers

2. Polymers from modified starch

They present better processability characteristics, but they have less

Starch: processability

They present better processability characteristics, but they have less

biodegradability

3. Blend of starch polymers and other polymers

They have better characteristics and processability. They are

processed with standard transformation technologies (i.e. extrusion,

thermoforming, blow moulding, injection moulding, foaming) with

little changes

Blends with other polymers require a deep formulative study to obtain a good

dispersion between phases.

Starch

Producers ProductsProductive capacity

[ton]Expansion [ton]

Novamont (I) Mater-Bi 60.000 80.000

Biotec / Sphere (F-D) Bioplast 15.000 50.000 (goal 200.000)

Biop (NL) Biopar 17.00065.000 (2012)

95.000 (2015)

Starch: producers

Rodenburg (D) Solanyl 40.000

Végéplast (F) Végémat 10.000 50.000 (2010)

Plantic (AU) Plantic 5000 10.000

Cardia Bioplastics

(AU)

Cardia

compostable10.000-15.000

DuPont with Plantic Biomax

Roquette (F) Gaialene 25.000

“

Starch: applications

L. Garavaglia AIM Polimeri da fonti rinnovabili Bologna 2005


L. Garavaglia : AIM Polimeri da fonti rinnovabili Bologna 2005




D.Castellanza: AIM Polimeri da fonti rinnovabili Bologna 2005


M.Malinconico


Fermentation of

glucose to give lactic

acid

Corn chemical

treatment to extract

starch

Corn destructuration to

give glucose

Harvesting

Polylactic acid - PLA

acid

Polymerization of

lactic acid


Purification and refining

→Starch extraction from corn

→Starch transformation in d-glucose (dextrose) through

enzymatic hydrolysis with pH values close to

neutrality, given the absence of acid catalysts

→ Glucose conversion in lactate through fermentation


→ Glucose conversion in lactate through fermentation

→ Then through a process of acidification and a series of

purification steps lactate, rich in salt, is refined to

obtain lactic acid

PLA is compostable, i.e. biodegradable in composting

conditions:

� temperature: 50 ÷ 60 °C

� presence of high humidity and microorganisms

� between 45 ÷ 90 days


� between 45 ÷ 90 days

At room temperature and outside composting conditions,

PLA is chemically and physically resistant to degradation, like

traditional polyesters


J.Lunt, Bioplastics reshaping an industry Las Vegas 1 febbr 2011

Lactic acid, monomer of PLA, is:

� A natural compound you can find in every animals.

� Used in food, cosmetic and pharmaceutical industry,

� Included in positive list of monomers admitted for food contact plastics.

Lactic acid: monomer

Lactic acid exists like stereoisomers L – or D -:

� Lactic acid, obtained through chemical synthesis, is made of a racemicmixture (50% D and 50% L)

� Fermentation is very specific and allows the production of a singlestereoisomer (99.5% L-isomer and 0.5% D-isomer), using specific bacilli

� Rate between two stereoisomers can differ in polymers, so those canhave different crystallinity and characteristics

Two different methods exist to obtain polylactic acid from

lactic acid monomer. They are different both chemically and

for the final polymer:

1. Direct condensation polymerization

Polylactic acid: polymerization


2. Ring-opening polymerization


Removal of water through condensation

a) using solvents

b) in high vacuum conditions


b) in high vacuum conditions

c) at high temperature

It has a great inconvenient: it produces only low/medium

molecular weight polymers, because of the difficulty of

removing completely water and other impurities.

2. Ring-opening polymerization


catalytic


Da NatureWork Giflex 2009

Three lactide monomers are produced: more controllability ofreaction. Pureness and possibility of high molecular weight polymers’production

Lactic acid is a chiral molecule and, for this reason, ring-

opening polymerization can create different kind of

polymers, each one with particular properties:


For example, if you have a stronger presence of L -

lactide, you will obtain a more crystalline polymer. On the

contrary, you will have an amorphous polymer.

Other possibilities of polymerization are:

Polymerization of blends of

two stereoisomers

Blending, at melt conditions,

of two stereopolymers


Stereo-block polymer Stereo-complex polymer

These products have high crystallinity levels and so, high

thermal properties.


�Density 1,25 g/cm3

�Transparent, glossy

�Good UV resistance

�Moderate O2, CO2 and water barrier

Polylactic acid: properties

�Moderate O2, CO2 and water barrier

�Weldable with different techniques

�Low resistance to solvents, acids and basis

�Food contact

Mechanical properties

�Tensile strength 50 – 60 MPa

�Young’s Modulus 3500 – 4000 MPa

�Elongation 1 – 5 %

�Izod 12 – 20 J/m

Polylactic acid: properties

Thermal properties

� Tg ~ 60°C, Tf 160-180°C,

� Vicat 65°C; HDT B 50-55°C

� Over 60°C PLA begins to degrade with high humidity

1. Low thermal resistance

It’s impossible to use with hot drinks, in microwave or

ironing applications

2. Fragility

Polylactic acid: critical points

2. Fragility

It creates problems in film extrusion and thermoforming

3. Low melt strength

It creates problems in blown extrusion and foaming

PLA crystallizes very slowly:

� It’s difficult to increase crystallinity level with

conventional process rate

� Thermal resistance remains low (about 60°C).


1. Low thermal resistance

Methods to increase thermal resistance:

→ Accelerating crystallization rate

1. With heterogeneous nucleating agents

2. Using d-lactide, which works like a crystallization

point (stereo – complex)

→ Adding natural fibers or mineral fillers

PLA Grade Vicat – average value (°C)

PLA 57,4

PLA + nucleating agent 102,9


→ Accelerating crystallization

rate with heterogeneous

nucleating agents

→Adding natural fibers

or mineral fillers

T. Yanagisawa 2^ European Bioplastics Conference, Paris 21-22/11/2007

→ To improve PLA’s low

impact resistance impact

modifiers, compatible with

PLA itself, were developed


2. Fragility

PLA itself, were developed

Main producers: Arkema

(Biostrength), DuPont

(Biomax) and DOW

(Paraloid).

B.Azimipour 2^ European Bioplastics Conference, Paris 21-22/11/2007

Chain extenders modify PLA rheological properties


3. Low melt strength

Source: Bioplastics Magazine 03/2008 pg. 35

→ PLA can be processed with standard transformation

technology, used for thermoplastic polymers (PET o PS) with

little changes.

→ It’s necessary to use hoppers with dryer to prevent humidity

absorption during injection moulding (over 100°C at melt

conditions PLA degrades because of humidity and there is a

Polylactic acid: processability

conditions PLA degrades because of humidity and there is a

fall of the molecular weight)

→ PET dryer can be used but with higher temperature (70 –

80°C) for 6 hours or more

→ During transformation process, you have to use more power

because of PLA particular rheological behaviour (shear

thinning)

1.00E+05

1.00E+04

Vis

cosi

ty

(Poi

se)

PLA


Rheological curve PLA vs PS

NatureWork Technical literature

1.00E+03

1.00E+02

Vis

cosi

ty

Shear Rate (rad./sec)0,01 1 100 1000

PS

PLA

THERMOFORMING

PLA is easily thermoformable on existing thermoforming

machines for PET, PS and PP with process rate similar to

PET’s ones.


FILM EXTRUSION

→PLA is interesting in film extrusion applications because of

its stiffness, transparency and brightness, similar to PET and

PS.

→ It has food contact approval

→ Haze 4,2; gloss 125

Barrier properties are:

� Advantageous in some cases (i.e. salad bags ready to use)

� Suitable for fast consumer products (i.e. yoghurt, gastronomy)

� Disadvantageous in case of long-life products (i.e. meat, fish)

� Irrelevant to applications without cover (i.e. eggs or tomatoes


� Irrelevant to applications without cover (i.e. eggs or tomatoes

packaging)

Barrier can be improved with:

1. Plasma coating with oxides of Si or Al

2. Metallization with Al

3. Easily coupling with other materials

BOTTLES

They have excellent transparency, brightness and mechanical

properties similar to PET’s ones, except creep.

a) Barrier properties:

1) good to aromas


1) good to aromas

2) low to water vapour

3) better than PP to O2 and CO2 but lower than PET

b) Recycle: identified by automatic readers, compostable or

recyclable by mechanical recycling

c) Higher cost of the resin (3x)

Producer Product Productive capacity [ton] Expansion [ton]

NatureWorks LLC Natureworks 140.000 450.000 (2020)

Mitsui Lacea 20.000 (2005)

Hisun Biomaterials Revoda 5.000

Futerro** Futerro pla 1.500 (2010)

Unitika* Terramac compounding

Polylactic acid: producers

Unitika* Terramac compounding

Teijin Biofront 200 10.000 (2020)

Pyramid

BioplasticsPyramid

Synbra 5.000 (2009) 50.000

Toray Ecodear

Toyota MotorsToyota

Ecopla1.000

* Unitika è un compounder ** jv Total e Galactic

Industrial sector % today % 2020

Packaging 70 20

Agriculture 1

Transports 0 20

Polylactic acid: applications

Transports 0 20

E/E 1 10

Fibers, tissues 28 50

Total 100 100

Fonte Utrecht University, Fraunhofer ISI


Thin film < 40 µm Rigid packaging – Without barrier


Rigid packaging – No food contact


Foam trays

Trays for gastronomy


Bacterium « Ralstonia eutropha »

Fermentation of

Storage of biopolymers as a reserve of carbon and energy

Cell disruption, separation, concentration, solvent Products in PHA

Polyhydroxyalkanoates - PHA

Fermentation of sugars in polymers inside cytoplasm of

cells

concentration, solvent extraction, drying

Products in PHA

PHAs are aliphatic polyesters, made directly in microorganisms

throughout fermentation of C substrate of natural substance in

cytoplasm of cells. C substrate is used like energy reserve:


At the end of fermentation (from 38 to 48 hours), cells are

concentrated, purified and extracted with hot solvent. Then PHA

has to be recovered from solution.

They are semicrystalline polymers with potentially very

interesting characteristics. Depending on the type of

microorganisms and on the raw material, they can be

produced like:

�Homopolymers (polyhydroxybutyrate)


Homopolymers (polyhydroxybutyrate)

�Copolymers (poly(hydroxybutyrate-co-

hydroxyvalerate)) or (poly(hydroxybutyrate-co-

hydroxyesanoate))

Properties are related to the quantities of co-monomers.

Properties of copolymers (3HB-co-3HV)

Properties PHBPHBV

(10% HV)

PHBV

(20% HV)

Melt point , °C 180 140 130

Tensile strength, MPa 40 25 20

Polyhydroxyalkanoates: properties

Tensile strength, MPa 40 25 20

Flexural modulus, MPa 3500 1200 800

Elongation at break, % 8 20 50

C.Bastioli Handbook of Biodegradable Polymers Rapra 2005, p.189

PHB vs PP


Ref. D, Scherzer NIChE February 5 – 8 2006, Orlando (USA)

PHA vs PLA

PHA (Polyhydroxyalcanoates) PLA (Polylactic Acid)

Natural polymers Natural monomer

Biodegradable Hydrolysable

Stable at humid conditions Instable at higher temperatures (>60°C)


Semicrystalline, not transparent Low crystallinity, transparent

Wide range of monomers D- and L-lactic acid

Wide range of comonomers Comonomers reduce thermal stability further

Tg from –35°C to +10°C Tg 50°C

Strong and ductile Fragile

Temperature exercise <120°C Temperature exercise <60°C

� Insoluble in H2O

� It can be used at high temperature, also with hotdrink (HDT >120°C)

� High resistance to solvents, oils and fats


� High resistance to solvents, oils and fats

� Low resistance to acids and basis

� High UV resistance

� Good printability

It can be processed with traditional transformationtechnologies used for thermoplastics.

Humidity rate of granules must be within 0,1%.

Degradation temperature is near melt temperature, so it’s

Polyhydroxyalkanoates: processability

Degradation temperature is near melt temperature, so it’sadvisable to:

�Prevent too much high injection pressures and screwspeed

�Prevent too much high stationing time

Producers Products Productive

capacity [ton]

Expansion

[ton]

Metabolix* Mirel 2013

Meredian (tecnologia P&G)

(USA)

13.600 91kton/a

PHB Industrial (BR) Biocycle

Biomer (D) Biomer

Polyhydroxyalkanoates: producers

Biomer (D) Biomer

BioMatera (CDN) BioMatera

PHA

1000 100000

Kaneka (J) PHBHx 1.000 (2010) 50.000

Mitsubishi Gas Chemical BioGreen 10

Tianan Biologic Material (RCH) Enmat 10.000 10-50.000

DSM-Tianjin Green Bioscience 10.000

Shenzen Ecomann

Biotechnology Co

EM 5.000 50.000

Industrial sector % today% 2020

Mirel

Packaging 80 20

Buildings 20

Agriculture 20 20

Polyhydroxyalkanoates: applications

Transports 0 0

E/E 0 20

Fibres, tissues 0 10

Others 0

Total 100 100

PRO-BIP 2009

Polyhydroxyalkanoates: applications

Biomonomers have been already used from time to produce

polymers in combination with fossil monomers.

The goal is to:

Biomonomers

�Decrease oil consume, reaching a significant

environmental improvement

�Produce polymers (polyesters, polyamides,

polyurethanes, epoxy resins) with technological

characteristics that make them suitable for engineering

applications and durable goods.

Tendency on the market is to

A lot of societies have the goal to realize polymers, until now

produced from fossil resources, using renewable resources.

use biopolymers from renewableresources monomers, even if they arenot biodegradable

Biomonomers

can replace similar traditional materials already on the market

let producers to use existingtechnological equipments withoutchanges

produced from fossil resources, using renewable resources.

The advantage, in comparison with the other biopolymers, is

that the obtained products

Monomer Producer Source Developments Polymer

ethylene

Braskem sugar 200. 000 t/y bioPE

Jv Dow/Crystalev sugar 350.000 t/y bioPE

Solvay bioethanol 60.000 t/y bioPVC

propylene Braskem sugar 30.000t (2013) bioPP

1-3 propanediolJv DuPont/

sugar 45.000 t/y

Polyols,

intermediate

Biomonomers

1-3 propanediolJv DuPont/

/Tate&Lylesugar 45.000 t/y intermediate

biopolyesters

1-4 bio BDOj.v. Novamont/

Genomaticasugar Future 20.000 t

Intermediate

for

biopolyesters

1,4 BDO BioAmbersuccinic

acidFuture 23.000 t/y PBS

butadiene Genomatica biomassJV with Versalis

and Novamontelastomers


acrylic acid Jv Cargill/Novozymessugar→

3HPAIn development

Fibers, MP,

varnishes

Acrolein,

acrylic acidArkema

Glycerol

from

biomass

sebacic acid DuPont In development Intermediate PA

Biomonomers

sebacic acid DuPont In development Intermediate PA

Succinic acid *

Bioamber glucose3000 t/y Francia

35000 t/y Canada

65000 t/y Tailandia

Intermediate

PBS, PU, PA

Jv DSM/Roquette

(Reverdia)Starch

Pilot 2009

10.000t 2012

(Italia)

intermediate

Basf/Purac Impianto 2010 Intermediate

MyriantGlucose/

Biomass15.000t/y 2013

Intermediate

PBS,PA,PU

* Other researches from Mitsubishi Chemical


methacrylic

monomer

Röhm

Haas/Ceresbioethanol PMMA

caprolactam Draths Corp. lysine Plant 2015 Intermediate PA

terephthalic acid Draths Corp. glucose Plant 2015Intermediate

polyesters

Biomonomers

polyesters

isobutanol Gevo Inc.

Corn,

sugars,

biomass

pilotIntermediate for

biomonomers

isoprene Goodyear elastomer

epichlorohydrin Dow Intermediate

acid

furandicarbossilicAvantium

Sugars from

corn, reeds

400t 2013;

30-50Kt in 2015

Intermediate

polyester, PA,PU

Monomer Producer Source Polymer

Bayer oils monosaccharides Intermediate PU

Dow soybean oil Intermediate PU

DSM Soybean oil Foams, coating

Cargill soybean oilIntermediate PU

(foams)

Urethane Soy

System Cosoybean oil foams, adhesives

Biomonomers

polyols

Urethane Soy

System Cosoybean oil foams, adhesives

Vertelius Castor oil PU coating

Basf Castor oil Intermediate PU

Mitsui Castor oil Intermediate PU

Roquette starch

Isosorbide:

Intermediate PU,

polyester, PC

IFS Chemicals Rapeseed oil Intermediate PU

Bio-based

TechnologiesSoybean oil Intermediate PU

� Among new monomers in development, heterocyclic or

aromatic monomers can give interesting developments.

→Terephthalic acid, TPA, allows to produce 100%

biobased PET.

Biomonomers

� There are two monomers in an advanced stage of

development,

→furandicarbossilico acid, FDCA

→isosorbide

The lack of capacity to meet the growing demand for

biopolymers and some current technical limitations for their

use in consumer durables are pushing towards the production

of hybrid materials, that is obtained by

mixture of a biopolymer and a fossil

polymer

Hybrid polymers

polymer

This approach, from an environmental point of view, allows to:

→reduce the use of petrochemical raw materials and obtain

environmental benefits in terms of reducing CO2 emissions in

the life cycle of the product

From a technical point of view the hybrid polymers allow the use

of biopolymers in most critical applications.

From an economic point of view, they allow a cost containment.

Producer Trade mark Biopolymer Fossil polymer

Cereplast (USA)Cereplast Hybrid

ResinTMTPS PP

Cerestech (CDN) Cereloy™ Eco TPS HDPE,LDPE, LLDPE, PP

CardiaBiopolymers (AUS) Cardia Biohybrid™ TPS Polyolefins

Teknor Apex (USA)

Tecnologia CerestechTerraloy TPS PP, HIPS, LLDPE

Bayer (D) Makroblend BC PLA PC

Hybrid polymers

Bayer (D) Makroblend BC PLA PC

PMTC (T) EcoHybrid® PLA/PHB PP, PTU, PETG

RTP (USA) RTP Hybrid PLA, Polyesters PC, PMMA, PE or ABS

PolyOne (USA) reSoundPLA/PHA

PolyestersVarious

Samsung Cheil (ROK) Staren PLA PC, ABS

Kingfa Ecopond PLA PC, ABS

ArkemaRNewPlexiglass

RnewAltuglassPLA PMMA

1. Optimization of biodegradable polymers formulations

through new bioadditives research

2. Study of durability to satisfy requests for duration of

Biopolymers: niche or mass market?


goods

3. End-life of thick molded parts (recyclability,

biodegradability and/or compostability)

It’s necessary to develop new reinforncing additives and

agents from natural resources, which can be added to

biopolymers.

Most of the materials, on the market today, are able to

respond to environmental requirements, but they have


respond to environmental requirements, but they have

limitations in their characteristics (thermal resistance,

processability, barrier properties, mechanical properties).

Compounding is The KeyCompounding is The Key






goods



To use biodegradable biopolymers for realizing

engineering or durable goods (transports, E/E, …) is

necessary to have deep information about their

durability/aging properties for indoor or outdoor


durability/aging properties for indoor or outdoor

applications.






goods




Study on recyclability problems (managed separately from

traditional materials):

1. The lack of composting chains (which are widely

available in some countries only) and the problems

associated with products of high thickness

could facilitate biopolymers recycling.could facilitate biopolymers recycling.

2. In the case of a high expansion of the biopolymers

market there is the problem of

need for development of dedicated lines of recycling.

3. In the case of development of non-biodegradable

biopolymers from natural resources,

can be used recycling techniques proved successfully

for fossil polymers.


Study on biodegradability/compostability problems (goods of

some millimeters thick, typical of injection molded parts)

1. In the case of composting processes of products of high

thickness must be considered that, even if thethickness must be considered that, even if the

biodegradation rate is not dependent on the thickness,

times to reach 90% biodegradation may be higher than

those required by the standard.

2. The size of the particles may be greater than those

prescribed.

Today biopolymers market is still a niche market,

� principally restricted to the packaging market and

agriculture

� estimated around 0,4 - 0,5% of the total consumption of

plastics

with a high rate of development according to many

Biopolymers: niche market

� with a high rate of development according to many

market researches (Freedonia Group 13%/year until

2013, Ceresana Research 17,8%/year until 2018, BCC

Research 34,3%/year until 2016, Nova Institute 340%

within 2020).

In some applications for agriculture and packaging, the use of

biopolymers also allows economic advantages (mulch film,

waste collection, food packaging, etc.).


To go over a niche market for biopolymers, it’s necessary to amplify the applications,

extending their use to applications most critical and also realizing:

� durable goods

� engineering applications

So it’s necessary to:


Improve properties

Reduce costs properties

To extend their use to most

critical applications

costs

1. Improved transformation

and production lines

2. Agreements with agricultural

industry to

produce biopolymers or

biomonomers at competitive

prices

Biodegradation is a process which occurs, typically, in two phases and

where substances and materials can be absorbed by microorganisms:

in this way, they can be placed back into the natural cycle.

1. Degradation, fragmentation: action of humidity, heat, UV, and/or

enzymes can reduce molecular chains and polymer resistance,

leading to fragmentation of the product

Biodegradability and compostability

Plastic

Fragments

plastic

Microbes

Humus

H2O

CO2

2. Biodegradation: fragments are consumed by microorganisms like

a source of food and energy and they are converted in CO2 and

H2O

BPI Biodegradable Product Institute – confused by the terms Biodegradable & Biobased

Fragments

plastic

Fragments

plastic

MARINE

PRODUCT USE/DISPOSAL

CONTROLLED UNCONTROLLED

WASTEWATER SOLID WASTE OPEN WATER SOIL

Biodegradability and compostability

AEROBIC

TREATMENT

ANAEROBIC

STABILIZATION

ANAEROBIC

TREATMENT

COMPOSTING BIOGASIFICATION LANDFILL

USE OF COMPOST IN

SOILC.Bastioli Handbook of Biodegradable Polymers, RAPRA

Order of aggressiveness regarding the biodegradation in

different environments

Compost > Soil > Fresh water > Marine water

C.Bastioli Handbook of Biodegradable Polymers, pag 165, RAPRA

Biodegradability

T + fungi +

bacteria dilute bacteriabacteria

Fungi +

bacteria

Biodegradability

Curve of biodegradation

Rate and level of biodegradation depend strongly on

environment in which the material is deposed:

�Humidity quantity

�Oxygen presence

Biodegradability

�Oxygen presence

�Temperature

�Concentration of microorganisms

�Concentration of salts

There are standards for all these situations

� Primary biodegradability (according to standard ISO):

Structural change (transformation) of a chemical

compound by microorganisms, resulting in the loss of a

specific property

� “Last” biodegradability (according to EN 13432):

Biodegradability

� “Last” biodegradability (according to EN 13432):

Decomposition by microorganisms of an organic

chemical compound:

1. in presence of oxygen, in CO2, water and mineral

salts and new biomass

2. in absence of oxygen, in CO2, CH4, mineral salts

and new biomass

Standard Conditions Determination

Disintegration

ISO 16929 Plastic Mat. composting pilot Aerobic

EN ISO 20200 Plastic Mat. lab scale

EN 14045 Packaging composting pilot aerobic

EN 14806 Packaging lab scale

Biodegradation

EN ISO 14855 Plastic Mat. composting cond. Aerobic CO2

EN ISO 14852 Plastic Mat. aqueous medium Aerobic CO2

EN ISO 14851 Plastic Mat. aqueous medium Aerobic O2

ISO 14853 Plastic Mat. aqueous medium anaerobic biogas

Standards

ISO 14853 Plastic Mat. aqueous medium anaerobic biogas

ISO 15985 Plastic Mat. high solid Anaerobic biogas

ISO 15985 app1 Plastic Mat. high solid Anaerobic biogas

EN ISO 17556 Plastic Mat. soil Aerobic O2/CO2

EN 14046 Packaging composting Aerobic CO2

EN 14047 Packaging aqueous medium Aerobic CO2

EN 14048 Packaging aqueous medium aerobic O2

requirements and

test methods

UNI 11183 Plastic Mat. Soil T amb. (domestic comp)

EN 14995 Plastic Mat. composting cond.

EN 13432 Packaging composting cond.

ISO 17088 Plastic Mat. compostable plastics

Aqueous medium

Biodegradation standards

Aerobic Tests Anaerobic Tests

soil Aqueous medium

ISO 14853

High solid

ISO 15985

Standards

CO2 evolved

ISO 14852

ISO 14853 ISO 15985

O2 requested

ISO 14851

Compost

ISO 14855;

EN 14046

Mineral bed

Composting

ISO 14855 emenda

In soil

ISO 17556

CO2 evolved

Aerobic biodegradation in compost

ISO 14855

CO2 evolution curve. Standard UNI EN 14855

� This method is based on the measurement of CO2 evolved to

calculate level and rate of biodegradation.

� The specimen, in granules, powder, film or simple shapes (max

2x2 cm), is mixed with mature compost and is left to incubate in

optimal conditions of O2, temperature and humidity(58°C, 50-

55%RH) to reproduce real conditions of a composting plant.

Aerobic biodegradation in compost

ISO 14855

55%RH) to reproduce real conditions of a composting plant.

� Temperature can vary in relation to material’s characteristics.

� Mature compost acts at the same time as support means, a

source of microorganisms (inoculum) and nutrients.

� Maximum duration of the test is 6 months. Average, duration is

45 days.

� At the same time, a reference sample (cellulose) is tested to

control inoculum activity and to validate the test.

There are two methods:

� ISO 14852 based on the measurement of the evolved CO2

� ISO 14851 based on the measurement of oxygen demand in a

closed respirometer

They have similar procedures:

�activated sludge from a sewage treatment plant that treats

principally municipal waste is considered to be an acceptable

Aerobic biodegradation in aqueous medium

principally municipal waste is considered to be an acceptable

active aerobic inoculum

� temperature is maintained preferably between 20 °C and 25°C,

in dark or diffused light for a minimum of 4 to 6 weeks and a

maximum of 6 months

� the test may be terminated once the sample has been at least

90% metabolized and if the CO2 evolution or O2 consumption

does not change significantly 72 h

ISO 14852 (Sturm test)


This method is based on the measurement of CO2 evolved to calculate level and rate of

biodegradation.

� Sample, preferably in powder (diam. max 2 μ), or also like a film, pieces, fragments

or simple parts. Because of the influence of the shape on the test (because shape

influences biodegradation rate), it’s necessary the same shape in tests with

comparative materials.

� Sample is placed in a mineral aqueous medium and an inoculum from activated

ISO 14852 (Sturm test)


Sample is placed in a mineral aqueous medium and an inoculum from activated

sludge, compost or soil is added and left to incubate.

� The mineral medium gives necessary nutrients and prevents pH variations.

� The mixture is left to incubate at constant T and it is agitated and aerated with CO2-

free air.

� Temperature can be typically between 20 - 25 °C (Tamb). Different temperatures, in

relation to the kind of inoculum and environment, are admitted.

� The test is carried forward until a plateau production of CO2 is reached. Maximum

duration is 6 months.

� The standard also provides the possibility of measuring the microbial biomass and

establishes the procedure.

This method is based on the measurement of consumed to

calculate rate and level of biodegradation.

ISO 14851 (MITI Test)

Aerobic biodegradation in aqueous method

Principles and procedures of the test are similar to those of

standard ISO 14852.

� The standard goal is to observe how a soil, which is not

acclimatized, works as an inoculum to simulate biodegradation

process in natural soil.

� Plastic material, which is the only source of carbon and energy,

is added to the soil (taken from superficial layers of fields and

ISO 17566

Aerobic biodegradation in soil

is added to the soil (taken from superficial layers of fields and

forests).

� Sample is placed in selected soil and it is incubated at 20 -25°C.

� Consumption of O2 or production of CO2 can be controlled.

� The test is carried forward until a constant value of

biodegradation is reached. Maximum duration is 6 months.

This method is based on the measurement of biogas

(methane) evolved to calculate level and rate of

biodegradation:

� Sample is placed in a mineral aqueous medium, added

with an inoculum (anaerobic sludge of treatment plant,

Anaerobic biodegradation in aqueous medium

ISO 14853

with an inoculum (anaerobic sludge of treatment plant,

wastewater) and left to incubate at a temperature of 30-

40°C and at a humidity content > 95%RH.

�Mineral medium gives necessary nutrients and prevents

pH variations.

�Some precautions are necessary to guarantee O2 absence

from the reactor

�Incubation duration is 6 months.

This method is based on the measurement of biogas

(methane) evolved to calculate level and rate of

biodegradation:

� Sample is added to a very active inoculum, which consists

of a residue obtained directly by a fermenter for the

Anaerobic biodegradation in high solid

ISO/DIS 15985

of a residue obtained directly by a fermenter for the

production of biogas or sewage sludge of civil wastewater

after elimination of water.

�Thermophilic temperature (52°C).

� Then the mixture is left to fermentate.

Biodegradation tests are always made at the same time on the

sample to test and on a reference sample, mainly constituted

of pure microcrystalline cellulose or polycaprolactone. The

average value of biodegradation of the material is expressed

in percentage and it is obtained from:

Biodegradability

100⋅⋅⋅⋅====

Bc

BmeBRme

� BRme: average value of biodegradation of sample totest, in percentage

� Bme: biodegradation of sample to test, in percentage

� Bc: biodegradation of reference sample, in percentage

100⋅⋅⋅⋅

====Bc

BRme

Compostable Biodegradable

Material

Compostability

Biodegradability is a

required condition but it is

NOT sufficient

Compostability can be defined like a specific form of biodegradation, which

occurs in composting plants both industrial and domestic.

Industrial composting is the transformation of organic waste in compost,

obtained in suitable plants, which guarantee the correct process control.

If the quantity of water and nutrients is enough high, microorganisms begin

to consume nutritive substances, and they degrade organic molecules,

producing CO2, water, biomass and heat. During the industrial process

temperature of about 60-70°C are reached and humidity arrives at 50-

60%RH.

Industrial composting

60%RH.

The standard which specifies requirements and procedures to determine

packaging and packaging materials composting possibility is UNI EN 13432.

UNI EN 13432 : “Requirements for recoverable

packaging through composting and biodegradation - Test

scheme and evaluation criteria for the final acceptance of

Composting

Standards for plastic materials in general have been written: UNI EN 14955.

scheme and evaluation criteria for the final acceptance of

packaging”.

To valuate compostability of a material is necessary to controlthe following parameters:

→ Material characteristics

→ Biodegradability

→ Physical disintegration

Composting

→ Physical disintegration

→ Compost quality

Tests and valutation criteria

Plastic MaterialsUNI EN 14995

PackagingUNI EN 13432

Concentration of heavy metals

Plastic materialsUNI 14995

PackagingUNI EN 13432

Material charcteristics

Composting

Maximum content of elements in plastics

Biodegradability of organic constituents

UNI EN 13432

Standard, which defines packaging compostability, establishes that:

A.2.1.1 The biodegradability shall be determined for each packaging

material or any significant organic constituent of the packaging material;

significant must be an indication that any organic constituent is present to

an extent greater than 1% of the dry mass of that material

Composting

an extent greater than 1% of the dry mass of that material

A.2.1.2 The total proportion of organic constituents without determined

biodegradability should not be greater than 5%

The same concept is expressed in the standard UNI EN 14995 in relation to

plastic materials.

Aerobic conditions

Biodegradation tests

Samples

≥ 50%< 50%

Anaerobic conditions

BRme

Composting

BRme

<90% ≥ 90%

Biodegradation tests

Not biodegradable Biodegradable

Not biodegradable

Biodegradability and disintegration levels

UNI EN 13432

Biodegradability

Level to reach must be 90% to reach in a time less than 6

months.

Composting

Disintegration

Samples of the material to test are composted together

with organic wastes for 3 months.

Residual mass of the material to test with dimensions > 2

mm must be less than 10% of the initial mass.

�Valuation of compostability both on pilot and on plant

scale.

�Samples of the material to test have to be composted

together with organic wastes for a maximum of 12

weeks.

Aerobic dinsintegration

ISO 16929

weeks.

�Material has to be disintegrated in invisible particles.

ISO 20200:2004 Plastics -- Determination of the degree of disintegration of

plastic materials under simulated composting conditions in a laboratory-scale

test.

Dinsintegration in compost

ISO 20200

Synthetic waste (2

days of test)

Compost (45

days of test)

� It’s much easier than ISO 16929 but it must be considered like a

preliminary screening test. Further tests are necessary to be able

to establish compostability.

� The mass of the residues of the final material with dimensions >

2mm must be less than 10% of the initial mass.

Dinsintegration in compost

ISO 20200:2004

� Disintegration at laboratory scale in simulated aerobic

composting process conditions

�Mature compost in composting plant

�Thermophilic temperature (58°C) for a minimum of 45 days and

a maximum of 90 days

�A sufficient aeration must be guaranteed

Do not discharge toxic substances into the environment

Compost quality

→ Compost is analyzed with typical physical-chemical parameters such as

pH, mineral salts content, density, N2, P, Mg and K.

→ Ecotoxicity tests can include tests on plants and/or other forms of life,

depending on the final application of the material.

→ Compost to test must not demonstrate a big difference (in negative)

Composting

→ Compost to test must not demonstrate a big difference (in negative)

with the white compost.

Today there are biopolymers that can substitute traditional plastic materials,

but it’s necessary:

→ to realize an optimization of process conditions relating to their

processability properties.

→ an adjustment of composting techniques

→ a rethinking of polymers recycling problems

Biomonomers development to produce “fossil” polymers lets to obtain

Conclusions

Biomonomers development to produce “fossil” polymers lets to obtain

polymers:

→ more sustainable from the industrial point of view

→ immediately useable in substitution of traditional fossil polymers

→ which don’t cause problems in the recycle chain (ex. PET)

A possible increase in oil products’ prices, the optimization of processes and an

adequate scale-up could let biopolymers be competitive economically too.

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