Polymer blends of brominated poly(phenylene oxide) derivatives and polyaminosiloxanes; synthesis and...

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" Polymer blends of brominated poly(phenylene oxide) derivatives and polyaminosiloxanes; synthesis and properties "
H. Tsai I. Cabasso

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1112470
Doc. No	:	TLpq303808990
Main Entry	:	H. Tsai
	:	I. Cabasso
Title & Author	:	Polymer blends of brominated poly(phenylene oxide) derivatives and polyaminosiloxanes; synthesis and properties\ H. TsaiI. Cabasso
College	:	State University of New York College of Environmental Science and Forestry
Date	:	1989
student score	:	1989
Degree	:	Ph.D.
Page No	:	325
Abstract	:	Multicomponent polymer blends consisting of polyaminosiloxanes and brominated poly(2,6-dimethyl-1,4-phenylene oxide) derivatives have been prepared and characterized. The kinetics and mechanisms of specific interactions and reactions between bromobenzylic and aminoalkyl groups of both model compound mixtures and polymer blends have been studied by Fourier transform nuclear magnetic resonance (FT-NMR) and infrared (FT-IR) spectroscopy. Spectroscopic data shows that both bromobenzylic and amino groups are involved in chemical reactions as evidenced by the reduction in signal intensity or the increase in chemical shifts monitored by H and C NMR spectrometers. The dipole-dipole interaction between the ether groups of poly(phenylene oxide) and polysiloxane bonds are observed by the infrared peak deformation. The acid-base type interactions (i.e., salt formation) as indicated by a series of NH2\sp+ vibration bands in the range 2000-3200 cm provided effective chemical linkages to stabilize the polymer blends. The thermal and dynamic mechanical properties of these blends determined by different techniques provide indirect evidence concerning the morphology. Detection of multiple glass transition temperatures suggests the existence of microdomains. The gas transport properties as functions of the composition and applied pressure are also described. The permselective properties of the alloy membranes are intermediate between those of the parent polymers, and vary with the composition. Their performance resembles random copolymers or compatible blends. In this case, gas penetrants serve as molecular probes to detect the level of miscibility in blends. The level of miscibility of polymer blends is also examined by the optical clarity and by the direct observation obtained from electron microscopy. Scanning electron micrographs with the aid of energy dispersive X-ray analysis of bromine and silicon maps do not indicate the existence of macrophase separation for transparent blends. Transmission electron micrographs show cellular or lamellar microdomains in the range 100-500 A and the aggregations of polyaminosiloxane-rich phases in the range 0.1-0.2 mum for transparent, homogeneous polymer blends over broad composition ranges. The segmental miscibility mainly depends on the average molecular weight between functional groups of the component polymers in the blends. Similar level of miscibility as full interpenetrating polymer networks or alternating block copolymers can be obtained.
Subject	:	Polymers
	:	Pure sciences