RESUMO
Poly(silylene diethynylbenzene)-b-poly(silylene dipropargyloxy diphenyl propane) copolymer (ABA-A), poly(silylene diethynylbenzene)-b-poly(silylene dipropargyloxy diphenyl ether) copolymer (ABA-O), and a contrast poly(silylene diethynylbenzene) with equivalent polymerization degree were synthesized through Grignard reactions. The structures and properties of the copolymers were investigated via hydrogen nuclear magnetic resonance, Fourier transform infrared spectroscopy, Haake torque rheometer, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis and mechanical tests. The results show that the block copolymers possess comprehensive properties, especially good processability and good mechanical properties. The processing windows of these copolymers are wider than 58 °C. The flexural strength of the cured ABA-A copolymer reaches as high as 40.2 MPa. The degradation temperatures at 5% weight loss (Td5) of the cured copolymers in nitrogen are all above 560 °C.
RESUMO
Silicon-containing arylacetylene resins with rigid conjugated structures in the main chain often exhibit poor processability. A strategy of improving the processability by destroying the molecular structure symmetry using side aromatic groups was proposed, and the effects of the side groups was further explored. Two novel structural resins with side aromatic phenyl and phenylacetylene groups (PODSA-2P-MM and PODSA-2E-MM) were synthesized by Grignard reaction. The side aromatic groups strongly interfere with the regular arrangement of the main chains, and the crystallinities of the resins decrease as compared with PODSA-MM resin without side aromatic groups. Due to the influence of the side aromatic groups, the novel resins exhibit good processability, low exothermic enthalpy, high modulus and good heat resistance.
