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Titolo:
Morphology and mechanical and viscoelastic properties of natural rubber and styrene butadiene rubber latex blends
Autore:
Varkey, JT; Augustine, S; Groeninckx, G; Bhagawan, SS; Rao, SS; Thomas, S;
Indirizzi:
Univ Akron, Inst Polymer Sci, Akron, OH 44325 USA Univ Akron Akron OH USA44325 kron, Inst Polymer Sci, Akron, OH 44325 USA Univ Oregon, Dept Ecol & Evolut Biol, Eugene, OR 97403 USA Univ Oregon Eugene OR USA 97403 Ecol & Evolut Biol, Eugene, OR 97403 USA Katholieke Univ Leuven, Dept Chem, Lab Macromol Struct Chem, B-3001 Heverlee, Belgium Katholieke Univ Leuven Heverlee Belgium B-3001 B-3001 Heverlee, Belgium Vikram Sarabhai Space Ctr, Propellant Engn Div, Thiruvananthapuram 695022,Kerala, India Vikram Sarabhai Space Ctr Thiruvananthapuram Kerala India 695022 a, India Mahatma Gandhi Univ, Sch Chem Sci, Kottayam 686560, Kerala, India Mahatma Gandhi Univ Kottayam Kerala India 686560 am 686560, Kerala, India
Titolo Testata:
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
fascicolo: 16, volume: 38, anno: 2000,
pagine: 2189 - 2211
SICI:
0887-6266(20000815)38:16<2189:MAMAVP>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
RHEOLOGICAL BEHAVIOR; ELASTOMERS; DIFFUSION; TRANSPORT;
Keywords:
latex blends; morphology; dynamic mechanical thermal analysis; natural rubber; prevulcanization; styrene butadiene rubber;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Varkey, JT Univ Akron, Inst Polymer Sci, Akron, OH 44325 USA Univ Akron Akron OH USA 44325 Polymer Sci, Akron, OH 44325 USA
Citazione:
J.T. Varkey et al., "Morphology and mechanical and viscoelastic properties of natural rubber and styrene butadiene rubber latex blends", J POL SC PP, 38(16), 2000, pp. 2189-2211

Abstract

The morphology and mechanical and viscoelastic properties of a series of blends of natural rubber (NR) and styrene butadiene rubber (SBR) latex blends were studied in the uncrosslinked and crosslinked state. The morphology of the NR/SBR blends was analyzed using a scanning electron microscope. The morphology of the blends indicated a two phase structure in which SBR is dispersed as domains in the continuous NR matrix when its content is less than 50%. A cocontinuous morphology was obtained at a 50/50 NR/SBR ratio and phase inversion was seen beyond 50% SBR when NR formed the dispersed phase. The mechanical properties of the blends were studied with special referenceto the effect of the blend ratio, surface active agents, vulcanizing system, and time for prevulcanization. As the NR content and time of prevulcanization increased, the mechanical properties such as the tensile strength, modulus, elongation at break, and hardness increased. This was due to the increased degree of crosslinking that leads to the strengthening of the 3-dimensional network. In most cases the tear strength values increased as the prevulcanization time increased. The mechanical data were compared with theoretical predictions. The effects of the blend ratio and prevulcanization on the dynamic mechanical properties of the blends were investigated at different temperatures and frequencies. All the blends showed two distinct glass-transition temperatures, indicating that the system is immiscible. It was also found that the glass-transition temperatures of vulcanized blends are higher than those of unvulcanized blends. The time-temperature superpositionand Cole-Cole analysis were made to understand the phase behavior of the blends. The tensile and tear fracture surfaces were examined by a scanning electron microscope to gain an insight into the failure mechanism. (C) 2000 John Wiley & Sons, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 23:21:12