New technique to quantitatively characterize crosslink density in ir and brominated poly(isobutylene-co-paramethyl styrene) blends | Health & Environmental Research Online (HERO)

HERO ID

6762813

Reference Type

Journal Article

Title

New technique to quantitatively characterize crosslink density in ir and brominated poly(isobutylene-co-paramethyl styrene) blends

Author(s)

Wang, YF; Wang, HC; ,

Year

1997

Is Peer Reviewed?

1

Journal

Rubber Chemistry and Technology
ISSN: 0035-9475
EISSN: 1943-4804

Publisher

AMER CHEMICAL SOC INC

Location

AKRON

Volume

70

Issue

4

Page Numbers

663-670

Language

English

DOI

10.5254/1.3538452

Web of Science Id

WOS:000072644600012

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0009574921&doi=10.5254%2f1.3538452&partnerID=40&md5=8645a306f346a04b60b3351e9ee41fb2
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Abstract

The physical properties and application performance of rubber blends are highly dependent on the curing behavior of blend components, morphology, and network structure. Crosslink density or molecular weight between crosslinks characterizes the network structure. It is desirable to develop correlations between product attributes, such as flex, ozone resistance, and permeability with crosslink density of the individual phase in the blend. This will aid developing high performance rubber blends via curative systems, elastomer components and concentration, bromine composition distribution, and processing condition optimization. One major road block is to quantitatively and unambiguously measure the individual phase crosslink density in the blend.A method has been developed and verified with solvent freezing point depression technique. The method can quantitatively determine the individual phase crosslink density in polyisoprene (IR)/Brominated Poly(isobutylene-co-paramethyl styrene) (BIMS) blends. The method is based on the principle that the molecular weight between crosslinks does not change in different solvents. This is coupled with mass balance equations to determine rubber volume fraction of each phase in the swollen blends. The crosslink density of each phase is then calculated by the Flory-Rehner equation.The method can evaluate the effect of curative distribution, processing conditions, and curative systems on GPR/BIMS blend performance. IR and BIMS blends were cured with zinc oxide and sulfur in this study. It was found that the IR and BIMS phase crosslink density reaches a plateau when the amount of the curing agent is greater or equal to 1.25 phr. The IR phase has a greater crosslinking density than the BIMS phase in the blends. These are valuable information to optimize the curative systems and enhance product attributes.

Conference Name

Spring ACS Rubber Division Meeting

Conference Location

MONTREAL, CANADA