8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 1/22

Volume ExpansionPolymerizations

Josh Katzenstein

CH392N

March 31, 2009

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 2/22

Outline

Background Dilatometry Expanding monomers

Different monomers Temperature dependence

Possible Explanation

Is there proof…? Applications Conclusion

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 3/22

“Normal” Behavior

Polymerizationleads to betterorganization ofmolecules

Organization packsmonomer closertogether

Result is a higherdensity polymerthan monomer

Salmone, Polymeric Materials Encyclopedia p.7550

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 4/22

Expansion

Why is this counter intuitive? Solids usually more dense than liquids:

Aluminum (ρs=2.548 g/cm3 ρL=2.368 g/cm3)

Copper (ρs=8.350 g/cm

3

ρL=7.937 g/cm

3

) Polymers more dense than monomers

Ethylene - 66% Shrinkage Styrene – 14.5% Shrinkage

BUT everyone has seen one thing thatdoes expand on freezing

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 5/22

ICE!

http://campaignprojects.wordpress.com/ 

2008/12/22/back-soon/ http://www.juneauempire.com/stories/ 020808/reg_245092689.shtml

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 6/22

Dilatometry

Definition: The measurement and study ofdimensional changes in polymers as afunction of temperature, fluid absorption,

mechanical stress or chemical reaction. Applications

% Crystalline (Presented by Brandon)

Extent of reaction Thermal expansion

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 7/22

Dilatometry – Thermal Devices

Thermal expansionmost common thing tomeasure bydilatometry

TMA: Thermo

Mechanical Analysis Older technique

Only good fortemperature

Bulb dilatometer Uncommon

Uses mercury

http://www.setaram.com/Thermo-Mechanical-Analysis-TMA-Dilatometry.htm

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 8/22

Dilatometry – ExpansionDevices

Measure capillary fluidheight as a function oftime

Track volumeexpansion of sample

In ‘normal’polymerizations thefluid level goes down(increased density)

Can also be used iffluid level goes updue to polymerexpansion 

Stuart, Polymer Analysis p. 91

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 9/22

Polymers That SupposedlyExpand

Early work done by Bailey (Univ.of Maryland) and Endo (TokyoInst. of Tech.)

First published as “Monomersthat Expand on Polymerization”(1976)

First materials were theorized todo this were: Spiro ortho esters Spiro ortho carbonates

Most volume changes were verysmall as measured (-0.1%-0.5%) Measured by “density gradient

tube method”

William J. Bailey

http://www.chem.umd.edu/About_Us/Newsletter/index2006.php

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 10/22

Spiro-Ortho Carbonates(SOCs)

General Scheme:

Catalyzed by Lewis Acids

Double ring opening polymerization

Sometimes either cationically or anionically

O O

O

O

O

O

O

O

O

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 11/22

Density Results

These are some examples of monomers thatstudies have shown expand onpolymerization

Sadhir, and Luck, Expanding Monomers (various pages)

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 12/22

Density Results - Temperature

Density of bothpolymer andmonomer aretemperaturedependent

Temperaturedependence isdifferent function

This is data by Endo

on 8,10,19,20-Tetraoxatrispiro-[5.2.2.5.2.2]heneicosane

Temp (ºC) Monomer

Density(g/cm3)

Polymer

Density(g/cm3)

Percent

Expansion

25 1.150 1.110 3.48

50 1.145 1.070 6.55

78 1.144 1.010 11.71

84 1.011 0.991 1.98

100 0.997 0.975 2.21

120 0.975 0.940 3.59

Endo et al, Makromol. Chem. 1976

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 13/22

Other Examples of PotentialVolume Expansion

Cyclic sulfates:

Cyclic carbonates:

Bicyclo-ortho esters:

Spyro-ortho esters:

Salmone, Polymeric Materials Encyclopedia p.7551

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 14/22

An Explanation – BondDistances

When molecules(monomers) are insolution they are keptapart by van der Wallsforces

Polymers, by definitionare held together bycovalent bonds

Van der Waalsdistance always biggerthan covalent distance

Salmone, Polymeric Materials Encyclopedia p.7551

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 15/22

Polymerization - General

A van der Waals bond (between monomers) isreplaced by a covalent bond Covalent < van der Waals => Overall Shrinkage

Polystyrene

No bonds broken, new bond formed between each monomer

Note: For condensation polymerization net effect is same

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 16/22

OO

Polymerization – Single RingOpening

Normally one van der Waals bond is replaced with onecovalent bond

In single ring opening one bond is broken and a van derWaals bond shifts to a covalent bond. One covalent broken in opening ring

van der Waals between monomers is replaced by covalentbond

Net result is still shrinkage New covalent bond makes whole network more dense

Bond broken Bond formed

Poly(ethylene oxide)

Overall shrinkage

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 17/22

O O

O

O

O

O

O

O

O

Polymerization – Double RingOpening

For every bond involving a shift from vander Waals to covalent TWO covalentbonds are broken

Net result is that the reduction in density

is counteracted leading to minimal, or noshrinkage, or potentially expansion

Bonds broken Bond formed

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 18/22

Is There Proof?

It appears so however… Most changes are very small

Dilatometry isn’t always very accurate

Sometimes minor structure changes made the differencebetween shrinkage and expansion

Explanations not always satisfactory Near van der Waals distances are bigger than covalent

distances

Why does is breaking two bonds enough?

Why does temperature dependence vary? Explanation could be as simple as ring strain release

So dispute continues…

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 19/22

Applications

Expansion materials: Stuff that fills cracks Precision moldings

Dental fillings

Rock cracking materials Zero expansion materials: Stuff that stays

the same

Strain-free composites Potting resins

Binders for solid propellants

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 20/22

Conclusion

“Normal” monomers shrink on polymerization Dilatometry is an effective tool for monitoringdensity changes Also good for thermal changes Can be used for extent of reaction in most systems

Double-ring opening polymerizations seem toshow expansion on polymerization

An explanation for this phenomenon might be

bond-distances Still dispute of explanation and whether or not thisphenomenon really happens

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 21/22

References

Salmone, Joesph. Polymeric Materials Encyclopedia. 1996

Luck and Sadhir. Expanding Monomers. 1992 Stuart, Barbara. Polymer Analysis. 2002 Bailey, W. J. and T. Endo (1978). "RADICAL RING-OPENING POLYMERIZATION AND

CO-POLYMERIZATION WITH EXPANSION IN VOLUME." Journal of Polymer SciencePart C-Polymer Symposium(64): 17-26.

Endo, T., M. Caisong, et al. (1982). "PREPARATION OF VINYL MONOMERSCONTAINING BICYCLIC ORTHO ESTER STRUCTURE." Polymer Journal  14(6): 485-

488. Endo, T., H. Katsuki, et al. (1976). "SYNTHESIS OF MONOMERS THAT EXPAND ON

POLYMERIZATION - SYNTHESIS AND POLYMERIZATION OF 8,10,19,20-TETRAOXATRISPIRO-[5.2.2.5.2.2]HENEICOSANE." Makromolekulare Chemie-Macromolecular Chemistry and Physics  177(11): 3231-3235.

Endo, T., M. Okawara, et al. (1982). "NEW MATERIALS WHICH CURE WITHOUTSHRINKAGE - PREPARATION AND POLYMERIZATION OF DIURETHANESCONTAINING BICYCLIC ORTHO ESTER STRUCTURE." Polymer Journal  14(11): 927-

930. Saigo, K., W. J. Bailey, et al. (1983). "SYNTHESIS OF MONOMERS THAT EXPAND ON

POLYMERIZATION - SYNTHESIS AND POLYMERIZATION OF 2,6,7-TRIOXABICYCLO[2.2.2]OCTANES WITH PHENYL GROUPS." Journal of PolymerScience Part a-Polymer Chemistry  21(5): 1435-1444.

8/13/2019 Polymer Expansion Presentation

http://slidepdf.com/reader/full/polymer-expansion-presentation 22/22

Thank you!

Any questions…?