Preparation and properties of polydimethylsiloxane-modified epoxy resins

Abstract

ABSTRACT:In this work, polydimethylsiloxane (PDMS) with different molecular weight were used to modify diglycidyl ether of bisphenol A (DGEBA). A PDMS-block-DGEBA copolymer that acted as a compatibilizer was prepared via DGEBA, hydroxy terminated PDMS, and silane coupling agent in the presence of a catalyst. The reaction mechanisms and compatibilizing effects of the block copolymer were studied by means of Fourier transform infrared (FTIR) spectrum analysis and observation under scanning electron microscopy (SEM). The thermal and mechanical behaviors were analyzed as well. Results indicated that the block copolymer has good compatibilizing effect, and PDMS with low molecular weight could be dispersed in the DGEBA matrix more evenly. Moreover, the PDMS modified DGEBA systems had higher impact strength and lower weight loss rate than those of the pristine DGEBA system.

Enhanced Charpy impact strength of epoxy resin modified with vinyl‐terminated polydimethylsiloxane

“…Since rubber modifiers are widely used as toughening agents of ER, we carried out investigation in order to compare our and published previously results. The value of impact strength of similar system (ER modified by rubber elastomers) is comparable/or better than those stated in Table IV, that is, Ozturk et al, 6 Lin et al, 18 Thomas et al, 36 Mathew et al, 37 Miwa et al, 38 even in the case of modification with block copolymer Zhao et al 48 As for the storage modulus, we obtained a decent value of 2000 MPa, which is in the upper half of values from Table IV with 3000 MPa (for 15 wt % of CTBN) 9 being the highest recorded value. As can be seen from the table glass transition temperature of our sample is one of the highest from compared systems stated in Table IV.…”

“…Table IV summarizes physicomechanical properties of ER depending on curing agents and modifiers as this significantly affect mechanical properties and T g of final product. 18,36,38,48 CONCLUSIONS 1. The value of impact strength of similar system (ER modified by rubber elastomers) is comparable/or better than those stated in Table IV, that is, Ozturk et al, 6 Lin et al, 18 Thomas et al, 36 Mathew et al, 37 Miwa et al, 38 even in the case of modification with block copolymer Zhao et al 48 As for the storage modulus, we obtained a decent value of 2000 MPa, which is in the upper half of values from Table IV with 3000 MPa (for 15 wt % of CTBN) 9 being the highest recorded value.…”

Modification of epoxy resin with polyether-grafted-polysiloxane and epoxy-miscible polysiloxane particles

“…The T g s of the cured modified epoxies are slightly lower than that of the cured neat epoxy. The lower T g s of modified epoxies can attribute to the very low T g of polysiloxane (-123 o C), 28 the plasticization of the polyether chains and the descending cross-link density of the epoxy networks.…”

Epoxy terminated polysiloxane blended with diglycidyl ether of bisphenol‐A. 1: Curing behavior and compatibility

“…For decades, many efforts have been made to overcome this problem. Functionalized polysiloxanes bearing reactive end groups (hydroxyl, carboxyl, amine, and epoxy) were used and incompatibility could be reduced through copolymerization, for example, the polycondensation reaction and then siloxane oligomers could be incorporated into the epoxy resins …”

“…For decades, many efforts have been made to overcome this problem. Functionalized polysiloxanes bearing reactive end groups (hydroxyl, [6][7][8][9] carboxyl, 10,11 amine, and 3,5,12-19 epoxy) were used and incompatibility could be reduced through copolymerization, for example, the polycondensation reaction and then siloxane oligomers could be incorporated into the epoxy resins. 16 Among these functionalized polysiloxanes, epoxy functional siloxane is one of the promising routes to circumvent the issue of incompatibility between silicon-and carbon-based ingredients and may provide the desired properties.…”