Alder-ene polymers derived from allyl aralkyl phenolic resin and bismaleimides: carbon fiber composites properties

Abstract

aThe influence of structural variations in bismaleimides (BMIs) on Alder-ene polymerization of O-allyl aralkyl phenolic resin [O-allyl Xylok (OAX)] was examined. Toward this, three BMI functional monomers, viz. 2,2′-bis 4-[(4′-maleimido phenoxy) phenyl] propane (BMIP), 4,4′-Bismaleimido diphenyl methane (BMPM), and Bis 4-maleimidodiphenyl ether (BMPE), were blended with OAX in different molar ratios. The cure characterization revealed that the allyl-dominated blends cure by three distinct reaction steps whereas the maleimide-dominated blends exhibit a two-step reaction invariable with the maleimide structure. Introduction of more maleimide functionalities increased the T g and thermal stability of the co-cured network. Differences in the storage modulus values and T g of the BMI/OAX systems were correlated to the chemical structure of the BMI and crosslink density. Flexural, interlaminar shear strength (ILSS), and impact strength of the composites decreased systematically with the increase in maleimide content in the blend. Among the BMIs studied, T g , thermal stability, and ILSS retention at elevated temperature were superior for BMPM/OAX blend owing to their high crosslink density and rigid backbone of the system. Allyl-rich compositions exhibited improved mechanical properties owing to the better resin-reinforcement interaction as revealed from morphological analysis by scanning electron microscopy.

Physicochemical Characterization of Functional Lignin–Silica Hybrid Fillers for Potential Application in Abrasive Tools

“…In this case the Tg values increased from 206 °C to 250 °C and 252 °C. These effects may be the result of such factors as increased rigidity of the polymer chain, reduced free volume, and increased crosslinking density [31]. The glass transition temperature value is relative to chain flexibility and the free volume associated with the chemical structure of composites [32,33].…”

The Preparation and Properties of Terephthalyl-Alcohol-Modified Phenolic Foam with High Heat Aging Resistance

“…Terephthalyl alcohol is one of the raw materials of xylok resin [32,33,34]. An aralkyl group was introduced into the resin skeleton by a chemical reaction, thereby imparting excellent heat resistance, water absorption resistance to the material and improving the dielectric properties of the material.…”

A new high performance novolac-based polytriazole resin

“…The T g value of the cured NPTA-88 resin is 202°C. The cross-link density of the cured resin is relatively high at 6.14 mol m −3 , which was evaluated from the DMA result in the following equation 34 :…”

“…A single tan curve reveals the homogeneity of the cured resin. The T g value of the cured NPTA-88 resin is 202 C. The cross-link density of the cured resin is relatively high at 6.14 mol m À3 , which was evaluated from the DMA result in the following equation 34 : where G 0 is the storage modulus of the cured resin at the temperature T (T ¼ T g þ 40 C) and R is the gas constant. The thermal stability of the cured NPTA resin was determined by TGA.…”