Polysiloxanes for flame retardant applications.

摘要

Polymers such as Nomex and Kevlar have long been used as flame resistant polymers. However, they are both expensive and difficult to produce. The original stimulus for this work was to create a coating for fabrics that will mimic the flame retardant qualities of Nomex. This work has successfully created a flame retardant flexible coating for fabrics from crosslinked poly(dimethylsiloxane (PDMS) --co- 5-hydroxy/amino isophthalate), using a novel enzymatic synthesis. Short chain PDMS is co-polymerized with dimethyl 5-aminoisophthtalate then crosslinked using hexamethylenetetramine resulting in a rubbery solid. Thermogravametric analysis (TGA) results shows thermal degradation temperatures of 400°C. Heat release capacity from pyrolysis combustion flow calorimetry (PCFC), shows a 50% decrease with high crosslinking, vs. non-crosslinked poly(PDMS --co- 5-aminoisophthalate). Gas chromatography/Mass spectroscopy shows a change in the pyrolysis products in inert atmosphere after crosslinking.; In the hopes to increase the flammability resistance of polysiloxane polymers, co-polymers of 14-18% diphenyl, dimethyl siloxanes, as well as pure diphenyl polysiloxanes are co-polymerized with 5-hydroxy/amino isophthalate, using novel enzymatic synthesis. Poly(diphenylsiloxane --co- dimethylsiloxane --co- 5-hydroxy/amino isophthalate) shows an 15-30°C increase in degradation temperature, depending on linking group (ester vs. amide), vs. poly(PDMS --co- 5-aminoisophthalate). Pure poly(diphenyl polysiloxanes --co- isophthalate) shows an increase of 22-70°C depending on linking group (ester vs. amide) vs. poly(PDMS --co- 5-aminoisophthalate). PCFC shows very little change in heat release capacity vs. poly(PDMS --co- 5-aminoisophthalate), for copolymers of 14-18% diphenyl and dimethyl siloxanes with 5-hydroxy/amino isophthalate. Poly(diphenylsiloxane --co- 5-aminoisophthalate) shows at least a 50% reduction in the heat release capacity vs. poly(PDMS --co- 5-aminoisophthalate).; Poly(dimethylsiloxane --co- 5-hydroxyisophthalate)-graft-polyethylene glycol micelle nano-particles were created, for the use of compatibilization with hydrophilic polymers. Characterization is done with static as well as dynamic light scattering. The results were well defined micelles of 20-40nm average hydrodynamic diameter at concentrations above .01 mg/ml and below 2.5mg/ml, as well as temperature stability past 80°C.