【作者】 李秀杰；

【导师】 姜振华；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2011， 博士

【摘要】 近些年来人们大都采用ABx,A2+B3的方法制备超支化聚醚醚酮,然而上述方法分别存在着各自的优缺点,ABx的方法没有凝胶区,不存在凝胶现象,但是制备结构单一,末端官能团唯一；A2+B3的方法制备的超支化聚合物结构多样化,但是存在凝胶区范围比较大的问题,得不到较高分子量的超支化聚合物。A2+BB’2的方法制备超支化聚合物,凝胶区较A2+B3方法的小,可以得到分子量较大的超支化聚合物,结构也可多样化。所以,本文拟采用A2+BB’2的方法制备超支化聚醚醚酮,以实现其应用。采用两种不同结构的BB’2型单体,制备一系列的超支化聚合物。研究了A2+BB’2的聚合机理,并计算了不同比例的超支化聚醚醚酮支化度。选取了分子量最大,热稳定性能最好的氟封端超支化聚醚醚酮作为粘度调节剂,采用共混的方法制备了改性PEEK材料,研究了共混物的流变性能,力学性能,热学性能和结晶行为等。流变学数据表明,在剪切范围内共混物的剪切粘度低于线性聚醚醚酮的剪切粘度,超支化聚醚醚酮具有降低线形聚醚醚酮熔体粘度的作用。力学性能数据表明在添加量低于3%粘度调节剂时,机械性能较线性聚醚醚酮增加,当添加量超过3%时机械性能较线性聚醚醚酮降低。粘度调节剂的加入对材料的热稳定影响不大。超支化粘度调节剂对PEEK的结晶有促进作用。为了更大限度的提高支化型粘度调节剂的应用范围,我们制备了结晶型超支化聚合物。并对共混物性质进行了研究,流变学数据表明其具有降低线性聚醚醚酮的熔体粘度的作用。对力学性质,热学性能影响不大。更多还原

【Abstract】 Hyperbranched polymers have their unique physical and chemical properties due to their highly branched structure. Their globular shape, followed by the low hydrodynamic volume and melt viscosity make them can be used as a rheology modification for linear polymer with high melt viscosityA fast and highly efficient approach for the synthesis of hyperbranched poly(ether ether ketone)s (HPEEKs) via the polycondensation of A2 and BB’2 monomers is described. Commercially available hydroquinone (HQ, A2 monomer) and easily synthesized 3,4’,5-trifluorobenzophenone (TF-1, BB’2 monomer) and 2,4’,6-trifluorobenzophenone (TF-2, BB’2 monomer) were thermally polycondensed to prepared fluoro- or phenolic-terminated HPEEKs with K2CO3 and Na2CO3 as catalysts. During the reaction, the fluorine at the 4’-position of TF reacts rapidly with the phenolic group of HQ, forming predominantly dimers and some other species. The dimer can be considered as a new AB’2 monomer. Further reactions among molecules AB’2 and AB’2 with some other species result in the formation of HPEEKs. The structures of the resultant polymers was revealed by IR,1H-NMR and 19F-NMR spectra.19F-NMR spectra The degree of branching of fluoro-terminated hyperbranched poly (ether ether ketone) of TF-1 series was determined to be in the range 28-52%, whereas the degree of branching of phenolic -terminated hyperbranched poly(ether ether ketone) of TF-1 series was determined to be 100%. The degree of branching of fluoro-terminated hyperbranched poly (ether ether ketone) of TF-2 series was determined to be in the range 50-57%, whereas the degree of branching of phenolic -terminated hyperbranched poly (ether ether ketone) of TF-2 series was determined to be 100%. These hyperbranched polymers exhibit excellent solubility in general organic solvents, and possess moderate molecular weights with the broad distributions. Moreover, the structure and performance of the HPEEKs can be conveniently regulated by adjusting the type and feed ratio of the two monomers.Linear poly (ether ether ketone) (LPEEK) with high melt viscosity was blended with hyperbranched poly (ether ether ketone) (HPEEK) to enhance its melt process ability without sacrificing comprehensive performance. The advantage of using HPEEK was its unique spherical shape, low melt viscosity and its easy access. Rheological measurement showed that blending LPEEK with as little as 1% HPEEK resulted in about 17% reduction of melt viscosity for HPEEK of TF-2 series. LPEEK/HPEEK blends only existed one glass transition temperature (Tg), indicating complete miscibility which resulted from similar molecular structure. The HPEEK content, as heterogeneous nucleating agent and rheology modifier, accelerated the crystallization rate of LPEEK. Remarkably, the mechanical properties of LPEEK increased within 3% content of HPEEK. The good miscibility was proposed to be responsible for the improved mechanical properties. Moreover, the addition of HPEEK slightly increased the thermal stability of LPEEK.The above aforementioned hyperbranched poly (ether ether ketone) (HPEEK) was amorphous, which make the application of linear poly (ether ether ketone) (LPEEK) be limited if LPEEK and HPEEK were blended. So we try to prepare crystalline hyperbranched poly (ether ether ketone) using methods of homopolymerization and copolymerization. However, the crystalline hyperbranched poly (ether ether ketone) was not obtained using the methord of homopolymerization, because the homopolymerization was limited due to the activity. We adopted random copolymerization and block copolymerization to prepare the crystalline hyperbranched poly (ether ether ketone). In the case of random copolymerization, we prepared five ratios of hyperbranched poly (ether ether ketone), in which the ratio of TF-2: B2 was from 1:1 to 1:5. Hyperbranched poly (ether ether ketone)s were prepared successfully, as proven by NMR. Moreover, HPEEK was crystalline polymer when TF-2:B2≥1:3 TF-2: B2=1:3. In the case of block copolymerization, we also prepared five ratios of hyperbranched poly (ether ether ketone), in which the ratio of TF-2-OH:B2 was from 1:4.03 to 1:8.03. Hyperbranched poly (ether ether ketone)s were prepared successfully, as proven by NMR. Moreover, HPEEK was crystalline polymer when TF-2-OH:B2≥1:6.03. Linear poly (ether ether ketone) (LPEEK) and the resultant hyperbranched poly (ether ether ketone) (HPEEK) was blended. Four kinds of hyperbranched poly (ether ether ketone) (random copolymer, TF-2:B2=1:3 and 1:4; block copolymer, TF-2-OH:B2=1:6.03 and 1:7.03) were choosen as rheology modification. The results shows that the melting viscosity wasn’t reduced when the addition amount of random copolymer was 5%, while the melting viscosity reduced 20% when the addition amount of block copolymer was 5%,and their mechanical properties and thermal stability did not present obvious change.更多还原