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可溶性联苯型聚酰亚胺的合成及表征 被引量:3
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作者 李鹏 谢洪雪 +4 位作者 毕艳飞 谢腾腾 陈阔 候影飞 牛青山 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2023年第3期40-47,56,共9页
选用3,3',4,4'-联苯四甲酸二酐(BPDA)作为二酐单体,同时选用一种带有侧链的3,3'-二甲基-4,4'-二氨基二苯甲烷(DMMDA)作为二胺单体,采用两步法合成了可溶性的联苯型聚酰亚胺。探讨了单体配比、固含量、反应温度和反应时... 选用3,3',4,4'-联苯四甲酸二酐(BPDA)作为二酐单体,同时选用一种带有侧链的3,3'-二甲基-4,4'-二氨基二苯甲烷(DMMDA)作为二胺单体,采用两步法合成了可溶性的联苯型聚酰亚胺。探讨了单体配比、固含量、反应温度和反应时间等因素对聚酰胺酸黏度的影响,以及化学亚胺化时间对PI亚胺化程度的影响,并确定了聚酰亚胺最佳的合成条件。聚酰胺酸合成过程的最佳单体配比确定为1∶1,固含量为12%,反应温度为20℃,反应时间为8 h,最优条件下的聚酰胺酸特性黏度为1.88 dL/g;聚酰亚胺合成过程的最佳化学亚胺化时间为24 h,在该条件下亚胺化程度为98%。之后,对最优条件下合成的聚酰亚胺进行了一系列的结构和性能表征。结果表明,合成的聚酰亚胺相对分子质量较高(数均分子量(M^(-)_(n))和重均分子量(M^(-)_(w))分别为14万和21万)且分布较窄,在保持耐热性能和耐溶剂性能的同时,显著提高了成膜性、溶解性等加工性能,是制备耐溶剂纳滤膜的理想材料。 展开更多
关键词 聚酰亚胺 可溶性 合成 两步法
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Genome-Wide GRAS Gene Family Analysis Reveals the Classification,Expression Profiles in Melon(Cucumis melo L.) 被引量:1
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作者 yanfei bi bin Wei +4 位作者 Ying Meng Zhongzhao Li Zhenghui Tang Feng Yin Chuntao Qian 《Phyton-International Journal of Experimental Botany》 SCIE 2021年第4期1161-1175,共15页
Melon(Cucumis melo),belonging to the Cucurbitaceae family,is a globally important economic crop.GRAS(GAI,RGA,SCR)genes,which are a type of transcription factor,play a critical role in plant growth and development,incl... Melon(Cucumis melo),belonging to the Cucurbitaceae family,is a globally important economic crop.GRAS(GAI,RGA,SCR)genes,which are a type of transcription factor,play a critical role in plant growth and development,including processes such as radial root patterning,light signalling,abiotic/biotic stress,axillary shoot meristem formation,and phytohormone(gibberellin)signal transduction.In this study,the GRAS family in melon was analysed comprehensively with respect to chromosomal location,motif prediction,gene structure,and expression pattern.A total of 37 GRAS genes were first identified in melon,after which a phylogenetic tree was built with the GRAS genes of three model species(Arabidopsis,rice,and sacred lotus)and were divided into nine groups based on the findings of previous studies.Motif and gene structure analysis showed typical conserved domains in all melon GRAS and similar structures in the same subfamilies.The expression analysis of GRAS genes done using RNA-seq data,showed that these genes were differentially expressed in different melon leaves under powdery mildew stress.Furthermore,the real-time quantitative PCR for GRAS genes revealed gene expression corresponding to powdery mildew stress.Our results provide useful information for a better understanding of GRAS genes and provide the foundation for additional functional exploration of the melon GRAS gene family in the powdery mildew stress response. 展开更多
关键词 Genome-wide identification GRAS MELON stress response
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