线性PBS基脂肪族聚酯的合成和降解研究

为了探讨线性PBS基脂肪族共聚酯的结构和降解之间的关系,首先合成了线性PBS基脂肪族共聚酯,即聚丁二酸丁二醇酯-共-聚己二酸丁二醇酯P(BS-co-BA),聚丁二酸丁二醇酯-共-癸二酸丁二醇酯P(BS-co-BSe),并将线性PBS基脂肪族共聚酯及PBS在土壤悬浮液中进行降解,通过GPC、熔点测定仪对线性PBS基脂肪族共聚酯的分子量和熔点进行了测定;通过测定降解过程中失重率和降解前后聚酯薄膜表面形貌来对共聚酯降解程度进行表征。结果表明:随着二元酸碳链的增长,分子对称性降低,降解性能增大。通过观察分子量,熔点及降解失重率的测定结果,得出分子量越大,降解越不容易进行;熔点越小,降解性能越好。     

PBS及其共聚酯生物降解性能的研究进展

综述了PBS(聚丁二酸丁二醇酯)、PBS基脂肪族共聚酯,PBS基芳香族共聚酯的结构和生物降解性能,并分别总结了它们的结构和生物降解性能之间的关系.PBS基脂肪族共聚酯分为线型PBS基脂肪族共聚酯和枝状PBS基脂肪族共聚酯,分别对它们进行了介绍.得出了PBS及其共聚酯的结构、分子量、聚酯形态、熔点、结晶度等与共聚酯的生物降解性之间的关系.     

脂肪族聚酯的合成工艺及性能比较研究

对聚丁二酸丁二醇酯、聚丁二酸乙二醇酯、聚丁二酸己二醇酯/己二酸己二醇酯共聚物、聚乳酸以及聚己内酯等脂肪族聚酯的合成工艺及性能进行比较,通过比较探讨合成工艺和材料性能之间的关系,得出力学性能和分子量,性能和结晶度以及降解性之间的关系,为脂肪族聚酯的合成改性及降解研究提供思路。     

1,2-丙二醇对可生物降解聚丁二酸丁二醇酯的共聚改性

以丁二酸、丁二醇和1,2-丙二醇为原料,采用溶液结合熔融缩聚合成法,得到了一系列聚(丁二酸丁二醇酯-co-丁二酸1,2-丙二醇酯)共聚物P(BS-co-PS)。利用1HNMR、GPC和X射线衍射等方法对共聚物的组成、分子量及其分子量分布、热学性能、结晶性能、力学性能等进行了研究。结果表明:反应4h,即可得到数均分子量60000以上的聚(丁二酸丁二醇酯-co-丁二酸1,2-丙二醇酯)共聚物P(BS-co-PS),分子量分布均小于2.0;随着1,2-丙二醇添加量的增加,共聚物的结晶度降低,熔点下降,但断裂伸长率明显增加,当添加量为30%(摩尔分数)时,断裂伸长率达到417%,表明共聚物具有良好的延展性能;所有共聚物的热分解温度均在300℃以上,具有良好的热稳定性。     

丁二酸-1,4-丁二醇-尿素聚酯酰脲共聚物的制备与性能

在氩气环境下以丁二酸、1,4-丁二醇、尿素为原料,通过熔融缩聚、扩链反应合成新型可降解的丁二酸-丁二醇-尿素聚酯酰脲共聚物,并通过压延成膜法制得聚酯酰脲薄膜。采用傅里叶红外光谱(FT-IR)、核磁共振(1H-NMR)、凝胶色谱(GPC)、热重分析(TG)、差式扫描量热仪(DSC)、万能拉力机对聚合物及其薄膜结构及性能进行表征。结果表明:成功地合成了丁二酸-丁二醇-尿素聚酯酰脲共聚物,分子量可达7.3×104,熔点约为111.5℃,分解温度约为380℃。随着尿素含量的增加,共聚物薄膜拉伸强度增加,而断裂伸长率降低。经水解降解测试表明,引入尿素共聚改性PBS,可以提高共聚物的降解性能。     

聚丁二酸丁二醇酯的共聚改性

分别以乙二醇、己二醇、己二酸作为聚丁二酸丁二醇酯的共聚组分，合成了丁二酸丁二醇酯丁二酸乙二醇酯共聚物、丁二酸丁二醇酯丁二酸己二醇酯共聚物、丁二酸丁二醇酯己二酸丁二醇酯共聚物。用FT-IR和^1H-NMR对其进行了结构表征；GPC测试表明改性产物均具有较高的相对分子质量；DSC测试表明其熔点和结晶度较均聚物低，其拉伸强度有所降低，但断裂伸长率显著提高。     

PBS不同化学结构共聚物的性能

采用改变原料的组分合成不同化学结构的聚丁二酸丁二醇酯(PBS)改性共聚物:聚丁二酸丁二醇/己二酸丁二醇酯(PBS-co-BA)、聚丁二酸丁二醇酯/聚丁二酸乙二醇酯(PBS-co-ES)、聚丁二酸丁二醇酯/聚丁二酸己二醇酯(PBS-co-HS),利用FT-IR和1H-NMR表征共聚物的化学结构,并对共聚物的结构与物理性能、降解性能的关系进行对比.研究结果表明:所有共聚物的结晶度、熔点较其均聚物有所降低;但所有共聚物的断裂伸长率都有所提高.热分析结果表明:PBS-co-HS热性能有所提高,PBS-co-BA和PBS-co-ES有所下降.堆肥降解实验表明:所有共聚物的降解性都比均聚物有显著提高,其降解速度大小顺序为:PBS-co-BA>PBS-co-HS>PBS-co-ES>PBS,PBS-co-HS是综合性能最优良的材料.     

(丁二酸丁二酯/丁二酸己二酯)共聚物的合成及性能

以丁二酸、丁二醇、己二醇为原料,在十氢萘中进行直接缩聚反应,合成了高分子量(丁二酸丁二酯／丁二酸己二酯)共聚物,产率达到95％以上。FT—IR和^1H—NMR图谱表明,共聚物的结构为预期结构;GPC测试结果表明,共聚物均具有较高的分子量;与聚丁二酸丁二酯(PBS)相比,共聚物的拉伸强度显著降低,但断裂伸长率有所提高：DSC测试结果表明,共聚物的结晶度明显低于PBS,其熔点、结晶温度随体系中丁二酸己二酯单元的增加而降低：TG测试结果表明,共聚物均具有较好的热稳定性。     

聚丁二酸丁二醇酯的研究进展

聚丁二酸丁二醇酯作为一种生物可降解的脂肪族聚酯,应用非常广泛,但仍然存在着合成及性能方面的问题。综述了聚丁二酸丁二醇酯的合成方法,对比了其不同的改性手段,并指出了今后的发展方向。     

P(BS-co-BA)和P(BS-co-BSE)的合成与扩链研究

用癸二酸、己二酸部分取代丁二酸,通过熔融溶液相结合的聚合方法,得到两者一系列的共聚物。通过数均分子量和熔点两个指标,得出最佳取代比例为20%癸二酸取代丁二酸的共聚物(PBSE-20)和20%己二酸取代丁二酸的共聚物(PBSA-20)。用异佛尔酮二异氰酸酯(IPDI)对这两种共聚物进行扩链改性,结果表明:扩链后,其数均分子量大小顺序为PBS>PBSA-20>PBSE-20,分子量分布均小于扩链前;且断裂伸长率均大于扩链前,各聚合物的热分解温度均大于300℃。阐述了脂肪族聚酯分子量、熔点及分子结构对称性与降解性能之间的关系。     

聚酯的固相缩聚增粘

固相缩聚增粘是提高聚酯性能从而拓宽其用途的有效途径。对聚酯固相缩聚的理论和工业生产进行了较全面地介绍     

Syntheses of high molecular weight aliphatic polyesters in 1-alkyl-3-methylimidazolium ionic liquids

High molecular weight aliphatic polyesters were synthesized, for the first time, in 1-alkyl-3-methylimidazolium ionic liquids via two-step polycondensation. An oligoester with diol/diacid ratio higher than unity was essential for achieving high molecular weight product. Moreover, the molecular weight of the resulting polyesters was found to depend on the activity of the catalyst in the ionic liquids and the miscibility of aliphatic polyester/ionic liquid. The former factor was dominated by the anion of the ionic liquids. The latter factor could readily be tuned by varying the anion and/or the cation of the ionic liquids. A clear correlation was found between the miscibility of aliphatic polyester/ionic liquid and the extent to which their solubility parameters matched.     

Synthesis and characterization of high‐molecular weight aliphatic polyesters from monomers derived from renewable resources

A series of high‐molecular weight aliphatic polyesters have been synthesized, at temperatures of < 200°C, through a polycondensation reaction between 1,4‐butanediol and three diacids of different chain length (succinic acid, azelaic acid, and sebacic acid). All the polyesters obtained have a bio‐based content of 100% and number average molecular weight in the range of 28,000–116,000 Da. These average molecular weights are about 5–10 times higher than those of most reported aliphatic polyesters synthesized through similar reaction routes but at temperatures > 230°C. The over‐heating phenomenon, i.e., the observation of thermal degradation behavior of these polyesters at 230°C is reported. The crystallization behavior, mechanical properties, and enzymatic hydrolysis rate of the polyesters obtained are characterized. Poly(butylene succinate) (PBSu) shows the highest crystallinity and melting temperature, but the lowest thermal stability and slowest potential rate of enzymatic biodegradation rate compared with poly(butylene azelate) and poly(butylene sebacate). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40579.     

Crystallization and melting behavior of three biodegradable poly(alkylene succinates). A comparative study

Polyesters based on succinic acid and respective aliphatic diols, with 2–4 methylene groups were synthesized by melt polycondensation. Crystallization and melting behaviour of samples having the same molecular weight were studied. The odd–even effect was observed for the melting temperatures of these polymers. Poly(propylene succinate) exhibited the slower crystallization rates and lower degree of crystallinity, among these polyesters. In contrast poly(butylene succinate) showed the faster crystallization rates and higher degree of crystallinity. Multiple melting of the isothermally crystallized samples was attributed to partial melting re-crystallization and re-melting, as was revealed by MTDSC measurements and observations at fast DSC heating scans. The equilibrium melting points were found to be 114, 133.5 and 58 °C for PESu, PBSu and PPSu respectively. Also, the corresponding values for enthalpy of fusion were 180, 210 and 140 J/g. Spherulitic growth rates were analysed and the regime transition of PESu and PBSu was studied.     

缩聚法合成生物可降解聚酯研究进展

本文从分子设计的角度,综述了缩聚法合成生物可降解聚酯的研究进展,涉及脂肪族聚酯和含有芳香组分聚酯的合成。其中,对脂肪族聚酯 聚乳酸的缩聚合成,以及可再生资源用于聚酯的合成进行了重点介绍。同时也对一些合成聚酯的生物降解性能与结构的关系进行了讨论。     

Aliphatic polyester miscibility with polyepichlorohydrin

Based on the behavior of the glass transition for blends of polyepichlorohydrin with various aliphatic polyesters, miscible amorphous phases are formed in all cases when the ratio of aliphatic carbons to ester groups in the repeat unit is less than 10 but more than 2. This observation includes selected polyesters with branched and saturated cyclic units in their structure. Interaction parameters deduced from polyester melting point depression were all negative and showed a minimum within this range of polyester molecular structures. The composition dependence of the observed glass transitions was found to be severely influenced by the presence of polyester crystallinity in the blend when heated through the transition region.     

Phase behavior of blends of aliphatic polyesters with a vinylidene chloride/vinyl chloride copolymer

A series of aliphatic polyesters having CH₂/COO ratios from 2 to 14 in their repeat units were blended with a copolymer of vinylidene chloride containing 13.5% by weight of vinyl chloride. Blends of polyesters having CH₂/COO < 4 did not form completely miscible amorphous phases, whereas polyesters having CH₂/COO ≥ 4 did form completely homogeneous amorphous phases for all temperatures below the decomposition point except for the polyester with CH₂/COO = 14 which showed reversible phase separation on heating, i.e., lower critical solution temperature behavior. Interaction parameters were estimated by melting point depression and by analog calorimetry. The behavior reported here is qualitatively similar to that reported earlier for blends of aliphatic polyesters with poly(vinyl chloride), polyepichlorohydrin, polycarbonate, styrene–allyl alcohol copolymers, and the hydroxy ether of bisphenol A.     

Linear polymers with sulfur in the main chain. II. Synthesis of polyesters by interfacial polycondensation of bis(4,4′‐hydroxyphenyl)sulfide with several aliphatic acid dichlorides and their properties

The synthesis and properties of sulfur‐containing polyesters derived from bis(4,4′‐hydroxyphenyl)sulfide (TDP) and various acid dichlorides (AC) have been studied to evaluate the effect of the incorporation of sulfur in the main chains of polyesters. Polyesters derived from TDP and AC (with methylene numbers of 2–10) were synthesized by interfacial polycondensation in a 1,1,2,2‐tetrachloroethane /water mixture using tetra‐n‐butyl ammonium bromide as a phase transfer catalyst. Through the use of gel permeation chromatography, it was determined that the polyesters thus obtained had high molecular weights. The thermal properties of the polyesters including the TDP moiety were evaluated by thermogravimetry/differential thermal analysis and by differential scanning calorimetry. The analyses indicated that the polyesters including the TDP moiety were crystalline polymers with relatively high heat resistance. These polyesters were found to show an odd–even effect with the glass transition temperature and the melting point based on the methylene numbers. The tensile strength and storage modulus decreased with the methylene numbers. It was further found that the polyesters evidenced excellent barrier properties towards oxygen gas having an odd–even effect. In particular, it was shown that the polyesters with methylene numbers of 3, 4, 6, and 8 of methylene units have lower oxygen permeability than poly(ethylene terephthalate) (PET).©2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1865–1872, 2004     

增粘对PET结晶动力学的影响

利用差示扫描量热分析仪分析研究了增粘前后ＰＥＴ的结晶动力学。结果表明,ＰＥＴ增粘前后平衡熔点基本不变,半结晶时间增大,结晶速度常数减少。结合结晶的扩散因素和结晶成核界面能讨论了增粘前后的结晶特征的差别     

Polyesters containing sulfur. I. Products of melt polycondensation of diphenylmethane-4,4′-di(methylthioacetic acid) with some diols

Several new polyesters containing sulfur in the main chain were obtained by melt polycondensation of diphenylmethane-4,4′-di(methylthioacetic acid) with ethanediol, 1,3-propane diol, 1,4-butanediol, 1,5-pentenediol, 1,6-hexanediol, 1,2-propanediol, and 2,2′-oxydiethanol. The structure of all polyesters was determined from elemental analysis and infrared (IR) spectra. Yield, reduced viscosity, molecular weight, and softening temperature for reaction products have been found. Initial decomposition and initial intensive decomposition temperature were defined from the curves of thermogravimetric analysis.