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Titolo:
Effect of crosslinking on mechanical and viscoelastic properties of semiinterpenetrating polymer networks composed of poly(vinyl chloride) and isocyanate crosslinked networks
Autore:
Xu, X; Wang, L; Toghiani, H; Pittman, CU;
Indirizzi:
Mississippi State Univ, Dept Chem, Mississippi State, MS 39762 USA Mississippi State Univ Mississippi State MS USA 39762 State, MS 39762 USA Mississippi State Univ, Dept Chem Engn, Mississippi State, MS 39762 USA Mississippi State Univ Mississippi State MS USA 39762 State, MS 39762 USA
Titolo Testata:
JOURNAL OF APPLIED POLYMER SCIENCE
fascicolo: 7, volume: 78, anno: 2000,
pagine: 1402 - 1411
SICI:
0021-8995(20001114)78:7<1402:EOCOMA>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
SIMULTANEOUS INTERPENETRATING NETWORKS; POLY(METHYL METHACRYLATE); CASTOR-OIL; KINETICS; POLY(ETHYLENE-TEREPHTHALATE); CRYSTALLIZATION; POLYURETHANE; MORPHOLOGY; BEHAVIOR;
Keywords:
poly(vinyl chloride); isocyanates; polyol; semiinterpenetrating polymer networks; dynamic mechanical thermal analysis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Pittman, CU Mississippi State Univ, Dept Chem, Mississippi State, MS 39762USA Mississippi State Univ Mississippi State MS USA 39762 762 USA
Citazione:
X. Xu et al., "Effect of crosslinking on mechanical and viscoelastic properties of semiinterpenetrating polymer networks composed of poly(vinyl chloride) and isocyanate crosslinked networks", J APPL POLY, 78(7), 2000, pp. 1402-1411

Abstract

Semiinterpenetrating polymer networks (SIPNs) of PVC/isocyanate/polytriol were prepared by premixing small (150 mu m dia.) porous (30% voids) unplasticized PVC particles, 10% by weight of isocyanate, and a triol at differentOH/NCO mol ratios. Three types of isocyanates (methylene bis-phenyl diisocyanate (MDI), oligomeric NIDI isocyanates (PAPI), and toluene diisocyanate (TDI) prepolymer/polytriol) were used. Two-roll milling was followed by hot-press curing. The tensile, flexural, and impact strengths increased when small amounts of crosslinked isocyanate networks were created in PVC. The isocyanate/polyol hydroxyl stoichiometry was varied, and the effects of crosslinking on the tensile, impact, and flexural strengths of PVC/isocyanate/triol SIPNs were examined. The strength increments were greater when the OH/NCO mole ratio went from 0 to 0.25, than when it went from 0.25 to 1.0. In many cases, increasing OH/NCO mol ratio from 0.5 to 1.0 decreased tensile, impact, and flexural strengths. Both PAPI and MDI (30% NCO content) gave bigger improvements in the these mechanical strengths than the TDI (only 9.7% NCO). These SIPN blends exhibited lower tan delta peak temperatures and a single distinct loss modulus, E", peak values at lower temperatures than those of PVC that had been exposed to the same processing temperatures. Substantial amounts of isocyanate networks exist in SIPN phases according to DMTAstudies. The OH/NCO ratio did not generally correlate with the decreases in the glass transition temperatures in these three sets of blends. (C) 2000John Wiley & Sons, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/07/20 alle ore 06:26:38