No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

A new diacetylinic polymer was prepared through polycondensation of 4,4′-buta-1,3-diyne-1,4-diyldiphenol and dichlorodiphenylsilane. This aromatically substituted siloxane polymer contained thermally cross-linkable diacetylene links in the mainchain. FTIR, Raman, and 13C NMR analysis confirmed the diethynyl group was present in the polymer. DSC analysis showed the polymer had a T g of 130 °C, and a strong exothermic cure peak at 260 °C. Parallel plate rheological testing through monitoring of changes in viscosity confirmed the polymer cross-linked during heating. After curing above 260 °C, the polymer vitrified, with no detectable T g observed on subsequent reheating. The activation energy of thermally initiated curing of the diacetylene groups was estimated to be 120 ± 17 kJ/mol from DSC data using the Ozawa Flynn Wall method. TGA analysis in nitrogen starting from uncured polymer showed a 5% weight loss temperature of 541 °C and a pyrolysis yield of 82% at 800 °C.

Curcumin has attracted much attention due to its chemopreventive and anti-inflammatory properties. Here we describe the synthesis of poly[(arylenedioxy)(diorganylsilylene)]s via polycondensation between curcumin and various diorganodichlorosilanes. These novel polymers incorporate the β-diketone unit of curcumin as well as the Si−O bond in the backbone. The polymer structure was characterized by means of 1HNMR, FTIR, and elemental analysis, while GPC results showed high molecular weights. Preliminary cell culture results suggest lack of cytotoxicity, which is important for potential applications such as implant and scaffold materials. The T gs of these polymers are in the 24 to 131 °C range, tunable by altering the pendant organic groups. The un-cross-linked polymers are stable at 250 °C in air. The presence of vinyl groups in the backbone also allows the possibility for thermal cross-linking. DSC and rheology data demonstrate that the materials can cross-link at a temperature above 200 °C which suggests the feasibility of melt processing these polymers via a technique wherein a low viscosity polymer is made to flow into a heated mold where it cross-links over time and becomes a rigid thermoset material.