Poly (acrylonitrile-methyl acrylate) copolymer was synthesized by water depositing polymerization and has a typical feed ratio of 85/15. And then 1-3 wt% lauryl alcohol maleic anhydride (LAM) was adopted as stabilizer...Poly (acrylonitrile-methyl acrylate) copolymer was synthesized by water depositing polymerization and has a typical feed ratio of 85/15. And then 1-3 wt% lauryl alcohol maleic anhydride (LAM) was adopted as stabilizer to mix with the acrylonitrile based copolymer. The mixtures were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (1H NMR), Gel Permeation Chromatography (GPC), Differential Scanning Calorimetry (DSC), optic microscope and Ubbelohde viscosimetryr etc. The melting point (Tm) and glass transition temperature (Tg) of the 85/15 AN/MA copolymer mixed with LAM all decrease with the increase of stabilizer content. The lowest Tg and Tm were 116.1℃ and 209.1℃ respectively at the heating rate of 100℃/min when the content of LAM is 2 wt%. The 85/15 AN/MA copolymer mixed with 1-3 wt% LAM possess good thermal stability up to 30 min at 220℃.展开更多
Poly （butylene succinatc-co-terephthalate） （PBST） copolycsters were prepared by polycondensation. The crystallization behavior of the as-prepared copolyesters was investigated by depolarized light intensity （DLI...Poly （butylene succinatc-co-terephthalate） （PBST） copolycsters were prepared by polycondensation. The crystallization behavior of the as-prepared copolyesters was investigated by depolarized light intensity （DLI） at high undercoolings. According to Avrami equation, the exponent n, independent of the crystallization temperature, is at a range of 2. 5 to 3. 4, which probably corresponds to the heterogeneous mucleation and a 3-dimensional spherulitic growth. The maximum crystallization rate, very useful to polymer processing, was found at about 90℃ based on the half-crystallization time t1/2 analysis.展开更多
The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and ...The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and the ef-fect of sodium hypophosphite are especially emphasized,by FT - IR spectroscopy and acid- base titration anal-yses. The experiments reveal that carboxylic acids main.ly change to cyclic anhydride in the pre - drying step andSodium Hypophosphite (SHP) has effect on it, but mostester - crosslinkages are built in the curing step and SHPhas effects on both anhydride formation and ester -crosslinking formation.展开更多
基金Supported by National Natural Science Foundation of China (No.50573058)Specialized Research Found for the Doctoral Programof Higher Education (No.20050058004)
文摘Poly (acrylonitrile-methyl acrylate) copolymer was synthesized by water depositing polymerization and has a typical feed ratio of 85/15. And then 1-3 wt% lauryl alcohol maleic anhydride (LAM) was adopted as stabilizer to mix with the acrylonitrile based copolymer. The mixtures were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (1H NMR), Gel Permeation Chromatography (GPC), Differential Scanning Calorimetry (DSC), optic microscope and Ubbelohde viscosimetryr etc. The melting point (Tm) and glass transition temperature (Tg) of the 85/15 AN/MA copolymer mixed with LAM all decrease with the increase of stabilizer content. The lowest Tg and Tm were 116.1℃ and 209.1℃ respectively at the heating rate of 100℃/min when the content of LAM is 2 wt%. The 85/15 AN/MA copolymer mixed with 1-3 wt% LAM possess good thermal stability up to 30 min at 220℃.
文摘Poly （butylene succinatc-co-terephthalate） （PBST） copolycsters were prepared by polycondensation. The crystallization behavior of the as-prepared copolyesters was investigated by depolarized light intensity （DLI） at high undercoolings. According to Avrami equation, the exponent n, independent of the crystallization temperature, is at a range of 2. 5 to 3. 4, which probably corresponds to the heterogeneous mucleation and a 3-dimensional spherulitic growth. The maximum crystallization rate, very useful to polymer processing, was found at about 90℃ based on the half-crystallization time t1/2 analysis.
文摘The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and the ef-fect of sodium hypophosphite are especially emphasized,by FT - IR spectroscopy and acid- base titration anal-yses. The experiments reveal that carboxylic acids main.ly change to cyclic anhydride in the pre - drying step andSodium Hypophosphite (SHP) has effect on it, but mostester - crosslinkages are built in the curing step and SHPhas effects on both anhydride formation and ester -crosslinking formation.
