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用变温红外研究聚乳酸嵌段共聚物生成过程中的化学反应 被引量:2
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作者 李兰 徐红 +1 位作者 滕翠青 余木火 《材料科学与工程学报》 CAS CSCD 北大核心 2006年第5期670-672,共3页
本文采用熔融缩聚法合成一定分子量的聚乳酸(PLA),采用聚己内酯多元醇(PCL)的聚氨酯预聚体进行共聚反应,以制得PLA-PCL嵌段共聚物。采用变温红外研究了PLA预聚体与PCL预聚体的反应活性,并研究了共聚产物的分子量。结果表明,PLA预聚体与... 本文采用熔融缩聚法合成一定分子量的聚乳酸(PLA),采用聚己内酯多元醇(PCL)的聚氨酯预聚体进行共聚反应,以制得PLA-PCL嵌段共聚物。采用变温红外研究了PLA预聚体与PCL预聚体的反应活性,并研究了共聚产物的分子量。结果表明,PLA预聚体与PCL预聚体具有很高的反应活性,共聚后PLA的分子量有大幅度提高。 展开更多
关键词 聚乳酸 嵌段共聚物 反应红外 反应活性
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MoO_3/SO_4^(2-)-TiO_2 catalyst for transesterification of dimethyl cabonate with phenol 被引量:1
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作者 崔丽萍 李彦君 +1 位作者 李忠 赵君芙 《Journal of Central South University》 SCIE EI CAS 2014年第5期1719-1724,共6页
A new MoO3/SO4 2--TiO2 catalyst was prepared by a conventional impregnation of SO4 2-/TiO2 as carrier with an aqueous solution of ammonium molybdate and used for the synthesis of transesterification of dimethyl carbon... A new MoO3/SO4 2--TiO2 catalyst was prepared by a conventional impregnation of SO4 2-/TiO2 as carrier with an aqueous solution of ammonium molybdate and used for the synthesis of transesterification of dimethyl carbonate(DMC)with phenol.A series of MoO3/SO4 2--TiO2 catalysts with different MoO3 loadings were investigated and characterized using X-ray diffraction(XRD),Fourier transform infrared spectrometer(FTIR),NH3-temperature programmed desorption(NH3-TPD)and X-ray photoelectron spectroscopy(XPS).The results show that MoO3 loading is related to the activity of transesterification reaction.With the increase of MoO3 loading,the activity of transesterification reaction increases.The sulfur species in the catalyst have an influence on the molybdenum species,and lead to an increase in the electropositive of molybdenum,which promotes the catalytic activity of MoO3/SO4 2--TiO2.Among the series of catalysts prepared,MoO3/SO4 2--TiO2 with 10% MoO3 and 823 K calcinated is found to be the most active catalyst for transesterification reaction.Under the reaction conditions of 453 K and 12 h,the conversion of DMC is 30.5 %,and the yields of MPC and DPC reach 21.2 % and 8.7 %,respectively. 展开更多
关键词 dimethyl carbonate diphenyl carbonate TRANSESTERIFICATION MOO3
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