High glass transition temperature shape‐memory materials: Hydroxyl‐terminated polydimethylsiloxane‐modified cyanate ester

Abstract

Hydroxyl-terminated polydimethylsiloxane (HTPDMS) and hydrogenated bisphenol A-type epoxy resin (AL-3040) were coreacted with a silane coupling agent (KH-550) to form an AL-3040 epoxy resin-HTPDMS block copolymer. Then, the copolymer was used as a compatibilizer to modify cyanate ester with different mass ratios. Subsequently, the blend was cured to form HTPDMSmodified shape-memory cyanate ester. The soft Si─O─Si segments of HTPDMS act as a flexible unit that can be grafted with the crosslinked triazine structures of cyanate ester. It was excellent for the toughening modification of cyanate ester. With increasing mass ratio of compatibilizer and cyanate ester, the tensile strength and glass transition temperature (T g ) of HTPDMS-modified cyanate ester were decreased, whereas impact strength and elongation at break were increased. The shape-memory tests exhibited that HTPDMSmodified cyanate ester systems have excellent shape-memory properties with a shape recovery rate of >96% and shape fixity rate of >97% and a recovery time of less than 110 s. Furthermore, Thermo-Gravimetric Analyzer (TGA) tests showed that HTPDMS-modified cyanate ester exhibited good thermal stability; the temperature of 10% mass loss was high at 365 C. The char yield was increased with increasing contents of compatibilizer at 800 C. Therefore, HTPDMS modified cyanate ester exhibited much better heat resistance at high temperature. Figure 7. (a) The TGA curves of cyanate ester and HTPDMS-modified cyanate ester; (b) the DTGA curves of cyanate ester and HTPDMS-modified cyanate ester. [Color figure can be viewed at wileyonlinelibrary.com] ARTICLE WILEYONLINELIBRARY.COM/APP

Thermally resistant and strong shape memory bismaleimide resin with intrinsic halogen‐free and phosphorus‐free flame retardancy

“…Shape memory polymers (SMPs) are key materials for preparing sensors 1,2 and spatial self-expanding structures. 3 The rapid development of modern industry increasingly asks for SMPs with high heat resistance and suitable flame retardancy. 4 However, being organic polymers, almost all SMPs do not have excellent flame retardancy.…”

Influence of cyanate ester modifier on the thermal, mechanical, and corrosive properties of epoxy composite coating

“…It is well known that the movement of the molecular chain with a higher crosslinking density is constrained, thus a higher T g is obtained. [38]…”

“…However, the water absorption rate grows with the further increase of CE content, which is due to the corresponding increase of high crosslinking triazine rings with large intermolecular free volume. [38] Lots of water enters into the cavities, so a higher water absorption is achieved.…”

Design and Evaluation of a Cyanate Ester Containing Oxaspirocyclic Structure for Electronic Packaging

“…Thus, the resin should be toughened to meet the requirements of packaging performance, and the components must withstand high-speed and high-frequency conditions. The usual toughening methods are as follows: (1) a copolymerization with thermosetting resins [1][2][3], (2) a blend of hightemperature-resistant and low-dielectric thermoplastic resins [4][5][6], (3) the formation of an interpenetrating polymer network (IPN) with a rubber elastomer or block copolymer with linear macromolecules, [7][8][9][10][11], and (4) the introduction of polyhedral oligomeric silsesquioxane (POSS) or nanoparticles into the system [12][13][14]. Copolymerization with a thermosetting resin could perform a hybrid homogeneous network resin structure with improved properties but the limited toughening degree.…”