摘要
为探究可与酰胺基团发生相互作用的小分子对尼龙12(PA12)溶液结晶的影响,将γ-环糊精加入PA12的甲酸/二氯甲烷溶液中,成功制备了PA12/γ-环糊精复合物并从该复合物中提取出纯的PA12晶体。采用广角X射线衍射(WAXD)、差示扫描量热(DSC)法和傅里叶变换红外光谱(FTIR)证实了PA12/γ-环糊精复合物的形成,并对提纯PA12晶体的结构与性能进行了表征。发现该晶体具有更高的熔融温度,且在DSC升温过程中发生了Brill转变,呈现出分别高于PA12纯α晶和γ晶熔点12.3℃和12.1℃的两个熔融峰。WAXD结果表明,在该晶体中除了α晶和γ晶共存外,尚存在新的有别于α晶和γ晶的强衍射峰(2θ为22.5°)和肩峰(2θ为23.1°),表明环糊精影响PA12的结晶结构,使PA12分子链在环糊精形成的受限空间内有着更为伸展的构象和更为紧密的排列,这在物理性能上体现为更高的熔点。
To investigate the effect of small molecules that can interact with the amide group on the crystallisation of nylon 12(PA12)in solution,the PA12/γ-cyclodextrin complex was successfully prepared by addingγ-cyclodextrin to a formic acid/dichloromethane solution of PA12 and pure PA12 crystals were extracted from the complex.The formation of PA12/γ-cyclodextrin complex was confirmed by wide-angle X-ray diffraction(WAXD),differential scanning calorimetry(DSC)and Fourier transform infrared spectroscopy(FTIR),and the structure and properties of purified PA12 crystals were characterized.The crystal is found to have a higher melting temperature and undergo Brill transition during DSC heating,showing two melting peaks higher than the melting points of pureαandγcrystals of PA12 at 12.3℃and 12.1℃,respectively.The WAXD results show that in addition to the coexistence ofαandγcrystals,new strong diffraction peaks(2θof 22.5°)and shoulder peaks(2θof 23.1°)distinct fromαandγcrystals existing in this crystal,indicating that cyclodextrins affect the crystalline structure of PA12,resulting in a more extended conformation and tighter arrangement of PA12 molecular chain in the restricted space formed by cyclodextrins,which is reflected in the higher melting point in physical properties.
作者
李娜
夏铭辰
孙成
张景阳
付琳
扈健
薛美玲
Li Na;Xia Mingchen;Sun Cheng;Zhang Jingyang;Fu Lin;Hu Jian;Xue Meiling(School of Polymer Science and Engineering,Qingdao University of Science and Technology,Qingdao 266042,China)
出处
《工程塑料应用》
CAS
CSCD
北大核心
2023年第6期9-14,共6页
Engineering Plastics Application
基金
国家自然科学基金项目(51673104)。
关键词
尼龙12
晶体结构
复合物
环糊精
溶液结晶
nylon 12
crystal structure
complex
cyclodextrin
solvent crystallization
