物理化学学报2022，Vol.38Issue(8)：66-73,8.DOI:10.3866/PKU.WHXB202006029
可交联且可生物降解的高分子膜
Cross-Linkable Yet Biodegradable Polymer Films
摘要
Abstract
Polymer films are widely used as biomaterials,electronic devices,food packaging materials and gas separation membranes.In practice,cross-linking is an effective method to enhance their stability and increase the strength of these films.However,conventional cross-linked polymer films cannot degrade under mild conditions.Herein,we fabricated two cross-linkable,yet biodegradable,polymer films of～0.2 mm via solution casting using cinnamate-grafted polycaprolactones,namely:a poly((α-(cinnamoyloxymethyl)-1,2,3-triazol)caprolactone)(PCTCL133)homopolymer and a poly(caprolactone-stat-CTCL)(P(CL156-stat-CTCL28))copolymer.The successful syntheses of the polymers were confirmed via proton nuclear magnetic resonance(1H NMR)spectroscopy,size exclusion chromatography(SEC),and Fourier transform infrared(FT-IR)spectroscopy.The PCTCL homopolymer appeared as a transparent film,owing to its side groups that impede its crystallinity;in contrast,the copolymer film appeared translucent,owing to its PCL segments that are easily crystallized.The cinnamate groups facilitated the cross-linking of the polymer films when irradiated by ultraviolet(UV)light;this is indicated by its insoluble character in tetrahydrofuran,which is a good solvent for both polymers.SEC analysis indicated that a fraction of the P(CL156-stat-CTCL28)film remained un-cross-linked after irradiation,owing to its crystalline structure.In contrast,UV irradiation caused the PCTCL homopolymer film to become homogeneously cross-linked,which exhibited a cross-linking density of 49％after 2 h as indicated by the 1H NMR results.Thermogravimetric analysis(TGA)indicated that cross-linking of the PCTCL films caused a minimal change in thermal stability.Both the cross-linked polymer films were able to degrade upon the addition of a modest amount of concentrated hydrochloric acid,as confirmed by SEC and 1H NMR.However,the degradation rate significantly decreased after cross-linking,thereby indicating its tunable character that can be altered by varying the cross-linking density.In addition,the rate of degradation can be adjusted upon varying the fraction of cross-linked PCTCL groups in the copolymer.In principle,treating the polymer films with sufficient amounts of acid could form degradation products with molecular weights less than 300 g·mol-1.To further explore the mechanical properties of such materials,we investigated the correlation between the initial concentration used for solution casting and the Young's modulus of the film by employing molecular dynamics simulations.These results indicate that tougher films are prepared when using more concentrated polymer solutions,owing to a higher degree of chain entanglement.In summary,the prepared films with tunable degradability are promising materials for biomedical applications.In principle,this platform could be utilized in hydrogels and coating materials for a broad scope of applications.关键词
高分子膜/聚己内酯/光交联/可降解性/溶液浇铸法Key words
Polymer film/Polycaprolactone/Photocross-linking/Degradability/Solution casting分类
化学化工引用本文复制引用
陈帅,秦江雷,杜建忠..可交联且可生物降解的高分子膜[J].物理化学学报,2022,38(8):66-73,8.基金项目
The project was supported by the Natural Science Foundation of Hebei Province,China(B2018201140),State Key Laboratory of Organic-Inorganic Composites,China(oic-202001005),the National Science Fund for Distinguished Young Scholars,China(21925505),and the National Natural Science Foundation of China(21674081).河北省自然科学基金(B2018201140),有机无机复合材料国家重点实验室基金(oic-202001005),国家杰出青年科学基金(21925505)和国家自然科学基金(21674081)资助项目 （B2018201140）
