Properties and toughening of heat‐resistant thermosets based on unsaturated ester resins

Abstract

ABSTRACT:We describe our investigations of the curing chemistry and properties of heat-resistant thermosets comprised of unsaturated ester resins. We suggest a mechanism for the rearrangement of the cured matrix and volatile evolution during the curing process. We employed dielectric spectroscopy (DES) as a tool for monitoring the extent of cure, determining glass-transition temperatures, and evaluating electrical properties of the resins. We compare and contrast results obtained by DES to results obtained by dynamic mechanical analysis (DMA). Fracture testing showed that improvements were made in the toughness of these materials by blending the uncured resin with impact modifiers such as hydrocarbon or silicone reactive rubber adducts or poly(arylene ether sulfone)-based thermoplastic oligomers. We determined the effects of the thermoplastic toughening additive's molecular weight, concentration, and endgroup functionality on the phase separation, thermal stability, and fracture toughness of the blend.

Combination of polymerization and polycondensation in the synthesis, chemical modification, and cure of rolivsan thermosetting resins

“…5 –9 In the course of the first several minutes of the synthesis, after azeotropic condensation telomerization, the formation of oligoesters with end methacrylate groups and number average molecular mass of 800–1300 occurs (Figure 1). 8,18…”

“…19 –26 In some cases, ROLs contain internal ether groups (-Ar-CH(CH 3 )-O-(CH 3 )CH-Ar-) which were not completely cleaved during acidolysis. 8…”

“…[1][2][3][4] Development of these resins was started in the 1980s. [5][6][7] By now, a vast number of experimental data on rolivsan chemistry have been accumulated, that is, information about mechanisms of their formation [5][6][7][8][9][10][11] and cure, 4,5,[12][13][14] application areas, [1][2][3][4][5] and the new method for chemical modification that has been developed recently. [15][16][17] The present article is a review of our previous investigations and a new development focused for the first time on a substantial contribution of polycondensation to rolivsan chemistry in general and to ROL synthesis in particular.…”

Investigation of heterogeneous radical polymerization of methyl methacrylate with polydimethylsiloxane as stabilizing agent in supercritical CO2 by turbidimetry

“…Sc-CO 2 is a very poor solvent for most polymers, hence, except some fluorinated polymers and polydimethylsiloxane (PDMS), they precipitate during polymerization. 1 A review of the results in this area is given by Canelas and DeSimone. 1 Using amphiphilic CO 2 -soluble surfactants, as has already been done in the polymerization of vinyl polymers, 1 well-defined particles can be synthesized.…”

“…1 A review of the results in this area is given by Canelas and DeSimone. 1 Using amphiphilic CO 2 -soluble surfactants, as has already been done in the polymerization of vinyl polymers, 1 well-defined particles can be synthesized. DeSimone and coworkers obtained narrow particle size distributions by adding polydimethylsiloxane-methacrylate macromonomer (PDMS-MA) to methyl methacrylate (MMA).…”