Browsing by Author "YANG, T"

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COMPATIBLE SIMULTANEOUS INTERPENETRATING POLYMER NETWORKS BASED ON EPOXY-RESIN AND POLY(POLY(ETHYLENE GLYCOL)MALEATE)
(1993)
LIN, MS
;
JENG, KT
;
YANG, T
;
交大名義發表
;
應用化學系
Poly(poly(ethylene glycol)maleate) (PPEGMA) was synthesized from poly(ethylene glycol) of molecular weight 200 with maleic anhydride in a molar ratio of 1:1. PPEGMA was then blended with diglycidyl ether of bisphenol A (DGEBA) in various ratios. The formation of hydrogen bonds between PPEGMA and DGEBA was investigated with FTi.r. These blends were then cured with benzoyl peroxide and m-xylenediamine simultaneously to obtain simultaneous interpenetrating polymer networks (SINs). Cure behaviours via exothermic peaks were recorded by dynamic d.s.c. The SINs thus obtained were characterized with rheometric dynamic spectroscopy (r.d.s.) and d.s.c. to check the compatibility of the two constituent networks. Gel fractions were measured with a Soxhlet extractor using acetone as solvent. Hydrogen bonding in the PPEGMA/DGEBA blend was evidenced from the v(C=O) shift to lower wavenumber. During SIN formation, dynamic d.s.c. showed a shift of the exothermic peak to a higher and broader temperature range, indicating a network interlocking effect which was overcome by higher temperature. Full compatibility of PPEGMA/DGEBA SINs was found for all compositions. The compatibility between PPEGMA and DGEBA was supported from the inner shifts of a single damping peak in r.d.s. and a single glass transition in d.s.c. for each of the SINs.
KINETIC-STUDIES OF COMPATIBLE SIMULTANEOUS INTERPENETRATING POLYMER NETWORKS BASED ON POLY(POLY(ETHYLENE GLYCOL) MALEATE) AND EPOXY-RESIN
(1994)
LIN, MS
;
YANG, T
;
HUANG, KY
;
交大名義發表
;
應用化學系
A simultaneous interpenetrating polymer network (SIN) based on diglycidyl ether of bisphenol A (DGEBA) and poly(poly(ethylene glycol) maleate) (PPEGMA) in a 50/50 weight ratio was blended and was cured simultaneously by using benzoyl peroxide and m-xylenediamine as curing agents. Kinetic studies during SIN formation were carried out at 50, 60, 65 and 70-degree-C. Concentration changes of both epoxide and double bonds were monitored with Fourier-transform infra-red spectroscopy. Rate expressions were established with model reactions. Experimental results revealed that lower rate constants and higher activation energies for SIN were found compared with those for the formation of the respective component networks. A network interlock effect was proposed to account for this phenomenon. During simultaneous cure of DGEBA and PPEGMA, network interlock must provide a sterically hindered environment, which subsequently increased activation energies and reduced cure rates for both DGEBA and PPEGMA.
KINETIC-STUDY ON SIMULTANEOUS INTERPENETRATING POLYMER NETWORK FORMATION OF EPOXY-RESIN AND UNSATURATED POLYESTER
(1995-03-21)
LIN, MS
;
CHANG, RJ
;
YANG, T
;
SHIH, YF
;
應用化學系
Simultaneous interpenetrating polymer networks (SIN) based on diglycidyl ether of bisphenol-A (DGEBA) and unsaturated polyester (UP) in weight ratios of 100/0, 50/50, and 0/100 were blended and cured simultaneously by using cumene hydroperoxide (CHP) and m-xylenediamine (MXDA) as curing agents. A kinetic study during SIN formation was carried out at 43, 53, 58, and 64 degrees C. Concentration changes for both epoxide and C=C bond were monitored with Fourier transform infrared (FTIR). Rate expressions for epoxide polymerization were established with model reactions for phenyl glycidyl ether (PGE) and benzylamine in dichloroethane containing benzyl alcohol. Experimental results revealed that a lower cure rate constant for the C=C bond during SIN formation was found, compared with pure UP network formation. A model of network interlock is proposed to account for this phenomenon. During simultaneous cure of DGEBA and UP, the network interlock should provide a sterically hindered environment, which subsequently retards cure rate for UP. On the other hand, epoxide cure during SIN formation indicates higher rate constants for both uncatalyzed and catalyzed reactions, compared with those of pure DGEBA cure. Presumably the catalytic effect of hydroxyl end groups in UP overcomes the effect of network interlock. Kinetic parameters were calculated and are discussed. (C) 1995 John Wiley and Sons, Inc.