聚烯烃
对偶(语法数字)
高分子科学
材料科学
高分子化学
复合材料
艺术
文学类
图层(电子)
作者
Diego Ciardi,Benedetta Rigatelli,Emmanuel Richaud,Michel Cloître,François Tournilhac
出处
期刊:Polymer
[Elsevier]
日期:2024-03-01
卷期号:: 126864-126864
标识
DOI:10.1016/j.polymer.2024.126864
摘要
A statistical copolymer p (E-co-GMA) of ethylene and glycidyle methacrylate (4.5 wt%) is considered as a starting point towards semicrystalline networks with exchangeable links. Application of the binomial law to size exclusion chromatographic data suggests that chains deprived of reactive comonomers would represent less than 6 wt% of the total, allowing to expect the formation of high gel-content networks. Experimentally, up to 98 wt% gel is obtained upon modification with 3,3′-dithiopropionic acid (DTPA). The crosslinking reaction can be performed in the molten state through a 2-steps procedure: 1°) x mol. of a commercial grade p (E-co-GMA), y mol. of DTPA and z mol. of triazabicyclodecene (TBD) are sheared in a twin-screw compounder at 115 °C, a temperature right above the melting point of the polymer precursor, without triggerring the epoxy-acid addition; 2°) the thermolatent reactive blend thereby obtained is then crosslinked at 170 °C. Samples with x = 1, y = 1 to 4 and z = 0 to 0.8 were thus prepared and evaluated. The presence of TBD accelerates disulfide exchange reaction, possibly by involvement of the thiolate anion whereas it decelerates the epoxy-acid addition. The final networks present several characteristic properties of vitrimers such as insolubility in xylene above the melting point, thermo-activated stress relaxation and creep. Particular shape memory regimes, related to the semicrystalline vitrimer character and the high insoluble fraction are demonstrated. Eventually, production scale-up using continuous reactive extrusion is evaluated.
科研通智能强力驱动
Strongly Powered by AbleSci AI