The experimental data obtained from fast heating FTIR spectroscopy have confirmed that a conformational change occurs at about 135 ℃ for semicrystalline iPP. Based on the results of density and WAXD measurements, it ...The experimental data obtained from fast heating FTIR spectroscopy have confirmed that a conformational change occurs at about 135 ℃ for semicrystalline iPP. Based on the results of density and WAXD measurements, it can be inferred that the conformational change occurring at 135 ℃ comes from the disordering of helical sequences in non crystalline phase, which is further corroborated by the FTIR study on the chloride polypropylene.展开更多
薄膜镀层由于厚度小 ,难以用通常的磨损方法评估其耐磨性。本文研究了采用精密凹坑研磨仪评价薄膜镀层耐磨性的方法 ,并对 Ta N/ Nb N纳米多层膜和 Ta N、Nb N单层膜进行了磨损实验。结果表明 ,精密凹坑研磨仪是一种适用于评价薄膜镀层...薄膜镀层由于厚度小 ,难以用通常的磨损方法评估其耐磨性。本文研究了采用精密凹坑研磨仪评价薄膜镀层耐磨性的方法 ,并对 Ta N/ Nb N纳米多层膜和 Ta N、Nb N单层膜进行了磨损实验。结果表明 ,精密凹坑研磨仪是一种适用于评价薄膜镀层耐磨性的方法。Ta N/ Nb N纳米多层膜有比 Ta N、Tb展开更多
The new approach for synthesis of hyperbranched polymers from commercially available A2 and type monomers was extended to synthesize hyperbranched copolymers. In this work, hyperbranched copoly(sulfone-amine) was pr...The new approach for synthesis of hyperbranched polymers from commercially available A2 and type monomers was extended to synthesize hyperbranched copolymers. In this work, hyperbranched copoly(sulfone-amine) was prepared by copolymerization of divinyl sulfone (A2) with 4,4′-trimethylenedipiperidine (B2) and N-ethylethylenediamine ( ). During the reaction, secon-dary-amino groups of B2 and monomers react rapidly with vinyl groups of A2 monomers within 35 s, generating a type of intermediate containing one vinyl group and two reactive hydrogen atoms. Now the intermediates can be regarded as a new type monomer, which further polymerizes to form hyperbranched copoly(sulfone-amine). The polymerization mechanism was investigated with FTIR and LC-MSD. The degree of branching (DB) of hyperbranched copolymers increased with decreasing the ratio of 4, 4′-trimethylenedipiperidine to N-ethylethyl- enediamine, so DB can be controlled. When the initial mole ratio of B2 to was equal to or higher than four, r≥4, resulted copolymers were semi-crystalline, while copolymers with r＜3 were amorphous.展开更多
文摘The experimental data obtained from fast heating FTIR spectroscopy have confirmed that a conformational change occurs at about 135 ℃ for semicrystalline iPP. Based on the results of density and WAXD measurements, it can be inferred that the conformational change occurring at 135 ℃ comes from the disordering of helical sequences in non crystalline phase, which is further corroborated by the FTIR study on the chloride polypropylene.
文摘薄膜镀层由于厚度小 ,难以用通常的磨损方法评估其耐磨性。本文研究了采用精密凹坑研磨仪评价薄膜镀层耐磨性的方法 ,并对 Ta N/ Nb N纳米多层膜和 Ta N、Nb N单层膜进行了磨损实验。结果表明 ,精密凹坑研磨仪是一种适用于评价薄膜镀层耐磨性的方法。Ta N/ Nb N纳米多层膜有比 Ta N、Tb
基金the National Natural Science Foundation of China (Grant No. 29974017).
文摘The new approach for synthesis of hyperbranched polymers from commercially available A2 and type monomers was extended to synthesize hyperbranched copolymers. In this work, hyperbranched copoly(sulfone-amine) was prepared by copolymerization of divinyl sulfone (A2) with 4,4′-trimethylenedipiperidine (B2) and N-ethylethylenediamine ( ). During the reaction, secon-dary-amino groups of B2 and monomers react rapidly with vinyl groups of A2 monomers within 35 s, generating a type of intermediate containing one vinyl group and two reactive hydrogen atoms. Now the intermediates can be regarded as a new type monomer, which further polymerizes to form hyperbranched copoly(sulfone-amine). The polymerization mechanism was investigated with FTIR and LC-MSD. The degree of branching (DB) of hyperbranched copolymers increased with decreasing the ratio of 4, 4′-trimethylenedipiperidine to N-ethylethyl- enediamine, so DB can be controlled. When the initial mole ratio of B2 to was equal to or higher than four, r≥4, resulted copolymers were semi-crystalline, while copolymers with r＜3 were amorphous.
