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Properties of poly(styrene)‐“grafted” silk fibers and molecular weight of poly(styrene)
Author(s) -
Freddi Giuliano,
Ishiguro Yoshio,
Kasai Nobutami,
Crighton John S.,
Tsukada Masuhiro
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19960919)61:12<2197::aid-app20>3.0.co;2-3
Subject(s) - fibroin , polymer chemistry , silk , styrene , materials science , copolymer , monomer , aqueous solution , grafting , synthetic fiber , composite material , chemical engineering , chemistry , fiber , polymer , organic chemistry , engineering
Poly(styrene) was grafted onto silk fibers in an aqueous medium, using ammonium persulphate initiator. Add‐ons of up to 100% were achieved. The add‐on increased linearly with the monomer concentration of the grafting system, all other factors remaining constant. The yield of the reaction attained about 80% and the extent of homopolymerization was negligible. The equilibrium moisture regain decreased noticeably with increasing add‐on. Breaking load showed a tendency to increase in the 0–55% range of poly(St) content, while elongation at break and work of rupture decreased. The DSC endothermal peak at 315°C slightly shifted towards higher temperature by graft—copolymerization, and a new endothermal transition appeared beyond 400°C. TG measurements showed an increase of weight retention beyond 300°C for poly(St)‐“grafted” silk fibers. The dynamic mechanical behavior was characterized by a shift to lower temperature of the loss modulus peak. The transverse dimension of the fibers increased with increasing add‐on. The polymeric residue remaining after alkaline dissolution of silk fibroin showed a porous texture with a sponge‐like morphology. The molecular weight of poly(St) removed from silk increased up to 120 kDa in the 0–55% add on range and then remained constant. The “Poly(St)/Silk” molar ratio increased linearly over the add‐on range examined. © 1996 John Wiley & Sons, Inc.