Accession Number:

ADA151409

Title:

The Transformation of Liquid to Amorphous Solid. Effect of Reaction Mechanism on the Time to Vitrify for Linear and Network Polymerization,

Descriptive Note:

Corporate Author:

PRINCETON UNIV NJ DEPT OF CHEMICAL ENGINEERING

Personal Author(s):

• Aronhime, M. T.
• Gilham, J. K.

Report Date:

1984-11-01

Pagination or Media Count:

15.0

Abstract:

This reprint presents a model for calculating the time to vitrify of low molecular weight liquid on isothermal chemical reaction for linear- and network-forming polymerizations. For the linear case, the model is based on the glass transition temperature T sub g rising to the temperature of reaction T sub cure, and relationships between T sub g and molecular weight, molecular weight and extent of reaction, and extent of reaction and time. For the nonlinear case, crosslink density is used instead of molecular weight. Step- growth and chain reaction mechanisms are considered. In a plot of T sub cure versus time, the vitrification curve is generally S-shaped the time passes through a maximum just above the glass transition temperature of the unreacted monomers and passes through a minimum just below the glass transition temperature of the fully reacted material, which is in agreement with the limited available experimental data. The extent of reaction at vitrification is also presented. For the case of linear free-radical polymerization, existing free volume theory is also used to predict the extent of conversion at vitrification. Keywords include Epoxies, and Styrene.

Descriptors:

• *EPOXY RESINS
• *PHASE TRANSFORMATIONS
• *POLYMERIZATION
• *STYRENE PLASTICS
• *VITREOUS STATE
• AMORPHOUS MATERIALS
• LIQUID PHASES
• MOLECULAR WEIGHT
• REPRINTS
• SOLID PHASES
• TIME
• TRANSITION TEMPERATURE

Subject Categories:

• Plastics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE