Polyimides synthesized from siloxane-equilibrated 1,3-bis (3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride

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Abstract

Silicone polyimides were made with siloxane-equilibrated 1,3-bis (3,4-dicarboxyphenyl) - 1,1,3,3-tetramethyldisiloxane dianhydride (PADS) as the soft portion and [(1-methylethylidene) bis (4,1-phenyleneoxy)] bis-1,3-isobenzofurandione (BPADA) as the hard portion in combination with either para or meta-phenylene diamine. The silicone polyimides were made with varying siloxane chain lengths and with varying overall weight percent silicone. There were linear correlations between these variables and flexural modulus, percent elongation at break, and cut-through temperature. Glass transition temperatures were evaluated by dynamic mechanical analysis and the thermal stabilities were determined to be greater than 400°C by thermal gravimetric analysis. Melt viscosities were determined on the various copolymers and demonstrated a correlation between type of amine used, siloxane chain length, and overall weight percent silicone.

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