含乙烯基全氟聚醚-b-聚硅氧烷制备及其在硅橡胶中的性能

Preparation of vinyl-containing perfluoropolyether-b-polysiloxane and its properties in silicone rubber

  • 摘要: 耐溶剂性能差是制约硅橡胶发展与应用的重要因素之一,氟改性是解决该问题的有效手段之一。通过叔丁醇钾引发环硅氧烷阴离子开环制备了多乙烯基聚硅氧烷(Vi-PSi),与全氟聚醚硅氧烷反应制备含乙烯基全氟聚醚-b-聚硅氧烷嵌段共聚物(PFPE-b-PMVS),采用FT IR、1H NMR确定了其结构,并研究了PFPE-b-PMVS对甲基乙烯基硅橡胶(MVQ)力学性能、硫化性能、耐溶剂性能和热稳定性的影响。结果表明,随着PFPE-b-PMVS含量的增加,高温硫化交联后,改性MVQ的拉伸强度先增加后降低,当PFPE-b-PMVS添加量为2%时,拉伸强度和断裂伸长率可达11.38 MPa和396%;焦烧时间(t10)和正硫化时间(t90)随着PFPE-b-PMVS的增加而降低;耐溶剂性能随PFPE-b-PMVS添加量的增加吸附量降低,当PFPE-b-PMVS添加量为20%时,在对二甲苯溶剂中,吸附溶剂比未改性MVQ降低83.22%;热失重10%温度随PFPE-b-PMVS用量增加而降低。

     

    Abstract: Poor solvent resistance is one of the important factors restricting the development and application of silicone rubber, and fluorine modification is one of the effective means to solve this problem. Vinyl-containing polysiloxane (Vi-PSi) was prepared by potassium tert-butanol induced cyclosiloxane anionic ring-opening, and Vinyl-containing perfluoropolyether-b-polysiloxane block copolymer (PFPE-b-PMVS) was grafted with perfluoroether siloxane. Its structure was determined by FT IR and 1H NMR. The effects of PFPE-b-PMVS on mechanical properties, vulcanization properties, solvent resistance and thermal stability of methyl vinyl silicone rubber (MVQ) were studied. The results show that with the increase of PFPE-b-PMVS content, the tensile strength of modified MVQ increases first and then decreases after high temperature vulcanization crosslinking. When the addition of PFPE-b-PMVS is 2%, the tensile strength and elongation at break can reach 11.38 MPa and 396%. The coke time (t10) and positive vulcanization time (t90) decreased with the increase of PFPE-b-PMVS. The solvent resistance decreased with the increase of PFPE-b-PMVS. When the PFPE-b-PMVS added amount was 20%, the adsorption solvent in p-xylene solvent was 83.22% lower than that in unmodified MVQ. The 10% thermogravimetric temperature decreased with the increase of the dosage of PFPE-b-PMVS.

     

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