线形和枝化聚丁二酸丁二醇酯水解性能的研究

从重均相对分子质量(Mw)、熔点以及表面形态的变化,研究了线形和通过1,2,4-丁三醇枝化改性的聚丁二酸丁二醇酯(PBS)的水解性能。结果表明:PBS的Mw随着水解时间的延长而下降,线形PBS的Mw降低缓慢,枝化PBSMw降幅较大。水解过程中Mw的对数值与水解时间呈线性关系,水解经历了一个自催化的降解过程;水解后,PBS的熔点都有了不同程度的升高;SEM观察发现水解后膜片表面被侵蚀而变得粗糙,甚至有层状翘起现象。     

PBT/PC合金塑料的性能与微观结构

分别以丙烯酸酯与缩水甘油酯双官能化的乙烯类弹性体KT-22与具有"核-壳"结构的S-2001作为增韧剂,以聚对苯二甲酸丁二醇酯(PBT)与聚碳酸酯(PC)作为基体材料,通过熔融共混挤出工艺,制得高韧性的PBT/PC合金。研究了增韧剂含量对合金的力学性能、流动速率、维卡软化温度的影响;用SEM对PBT/PC合金塑料的断面形貌进行了分析研究。结果表明:增韧剂KT-22和S-2001对PBT/PC合金塑料具有良好的增韧作用,但弹性体S-2001的增韧效果优于弹性体KT-22。     

扩链改性聚对苯二甲酸丁二酯的力学性能研究

利用熔体流动速率测定仪、动态粘弹仪和电子拉力试验机等手段,考察了扩链改性对聚对苯二甲 酸丁二酯(PBT)的拉伸性能、熔体流动指数和动态力学性能的影响。实验结果表明:PBT经扩链改性后,随 其特性粘数增加,相对分子质量提高,熔体流动指数大幅度下降,玻璃化转变温度有所增加;改性后PBT的 储能模量和耗能模量提高2.6-4.6倍,拉伸强度提高50％以上,断裂伸长率提高1倍以上,表明扩链改性起 到了增粘增韧作用。     

聚丁二酸丁二醇酯的合成及性能研究

选取钛酸四正丁酯(TBT)和二(乙酰丙酮)钛酸二异丙酯(DIPEAT)单独或复配作为催化剂,采用直接酯化-缩聚法,合成聚丁二酸丁二醇酯(PBS),研究了TBT,DIPEAT,TBT-DIPEAT(摩尔比1∶1)3种催化剂对缩聚反应速度及合成产物的物理性能、热稳定性和流变性能的影响。结果表明:3种催化剂的催化活性由高到低依次为TBT,TBT-DIPEAT,DIPEAT;DIPEAT催化合成的PBS的相对分子质量分布较窄,物理性能较好;相比TBT催化剂,DIPEAT催化合成的PBS的热稳定性较好,PBS失重5%时热分解温度提高约12℃;以TBT,DIPEAT或TBT-DIPEAT作为催化剂,得到的PBS的流动曲线相似,熔体的表观黏度随着剪切速率的增大而减小,随着温度升高而降低,都是切力变稀型非牛顿流体。     

增韧改性聚对苯二甲酸丁二酯/聚碳酸酯共混物非等温结晶动力学与力学性能

The polybutylene terephthalate (PBT）/ polycarbonate (PC）blends modified by toughening agent（S-2001）consisting of methyl methacrylate, styrene and silicone were prepared via melt blending.The non-isothermal crystallization kinetics of the blends were investigated by scanning calorimetry (DSC）at different cooling rate of 5℃·min^-1,10℃·min^-1,15℃·min^-1, and the data were analyzed by using modified Avrami theories of the Jeziorny method.The influence of toughening agent相似文献   

Biodegradability and mechanical properties of agro‐flour–filled polybutylene succinate biocomposites

The objective of this study was the production of rice husk flour (RHF) and wood flour (WF) filled polybutylene succinate (PBS) biocomposites as alternatives to cellulosic material filled conventional plastic (polyolefins) composites. PBS is one of the biodegradable polymers, made from the condensation reaction of 1,4‐butanediol and succinic acid that can be naturally degraded in the natural environment. We compared the mechanical properties between conventional plastics and agro‐flour–filled PBS biocomposites. We evaluated the biodegradability and mechanical properties of agro‐flour–filled PBS biocomposites according to the content and filler particle size of agro‐flour. As the agro‐flour loading was increased, the tensile and impact strength of the biocomposites decreased. As the filler particle size decreased, the tensile strength of the biocomposites increased but the impact strength decreased. The addition of agro‐flour to PBS produced a more rapid decrease in the tensile strength, notched Izod impact strength, and percentage weight loss of the biocomposites during the natural soil burial test. These results support the application of biocomposites as environmentally friendly materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1513–1521, 2005     

新型钛系催化剂合成PBT树脂的性能研究

使用自制的新型钛系催化剂合成了PBT树脂切片,对照钛酸四丁酯合成切片,进行了常规性能、热性能、分子质量及其分布、流变曲线等分析研究,结果表明:自制催化剂所合成的PBT树脂切片的色相b值、端羧基值指标较优,分子质量分布较窄,结晶性能、热稳定性、流变性能等相当。     

Properties of ternary in situ polycarbonate/polybutylene terephthalate/liquid crystalline polymer composites

Ternary in situ polycarbonate (PC)/polybutylene terephthalate (PBT)/liquid crystalline polymer (LCP) composites were prepared by injection molding. The liquid crystalline polymer used was a versatile Vectra A950. The matrix of composite was composed of PC/PBT 60/40 by weight. A solid epoxy resin (bisphenol type‐A) was used as a compatibilizer for the composites. Dynamic mechanical analysis (DMA) showed that epoxy resin was effective to improve the compatibility between PC and PBT, and between PC/PBT and LCP, respectively. Tensile tests revealed that the stiffness of composites shows little change with the LCP content up to 10 wt %. Above this concentration, the stiffness tended to increase with increasing LCP content. Furthermore, the tensile strengths appeared to increase with increasing LCP content, and their values were close to those predicted from the rule of mixtures. Scanning electron microscopic examination showed that LCP ribbons and short fibrils were developed in the composites containing LCP content ≤10 wt %. However, fine and elongated fibrils were formed in the skin and core sections of the composites when the LCP content reached 25 wt % and above. Thermogravimetric analysis indicated that the thermooxidative stability of the PC/PBT 60/40 blend tended to improve with increasing LCP content. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1827–1835, 1999     

Biodegradable fibre reinforced composites composed of polylactic acid and polybutylene succinate

Abstract

Recent concern over the harmful effects on the ecology of long lasting plastics has led to heightened interest in the development of more environmentally sustainable materials. Attention has been paid to biodegradable thermoplastic polymers, polylactic acid (PLA) and polybutylene succinate (PBS). However, although these materials have been widely used as matrix in a composite, the potential of biopolymers as reinforcement in a composite structural system has been examined less. Two types of unidirectional biodegradable composites, PLA self-reinforced and PLA reinforced PBS matrix composites, were produced. The composites were tested for Young’s modulus, tensile strength and strain at break. Cross-section and fracture surface characteristics of the composites were also examined by scanning electron microscopy to identify damage modes. It is found that the tensile strength of both PLA self-reinforced and PLA–PBS composites is increased by 10–40%, while their initial modulus is 2–6 times higher than that measured for PLA and PBS films.     

Thermal,mechanical, and rheological properties of biodegradable polybutylene succinate/carbon nanotubes nanocomposites

Biodegradable poly(butylene succinate)/carbon nanotubes nanocomposites were prepared by melt mixing process, and the influence of carbon nanotubes on the properties of the nanocomposites was investigated. Differential scanning calorimetry showed that crystallization temperature (T_c) increase with increasing carbon nanotube content. Improvement of tensile modulus was observed by the addition of carbon nanotubes compared with pure poly(butylene succinate). Electrical conductivity showed that conductivity of polybutylene succinate/carbon nanotube composites increased with addition of carbon nanotube content. The storage moduli of polybutylene succinate/carbon nanotube composites are higher than the neat polybutylene succinate. The processability of polybutylene succinate/carbon nanotubes composites was improved and more pronounced in higher content of carbon nanotubes. POLYM. COMPOS., 31:1309–1314, 2010. © 2009 Society of Plastics Engineers     

The effects of melt grafted maleated polybutylene succinate on the properties of poly(hydroxybutyrate-co-hydroxyhexanoate)/polybutylene succinate blends

Poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHH)/poly(butylene succinate) (PBS) blends were prepared using a melt blending technique. A compatibilizer of maleated PBS (PBSgMA) was produced using reactive melt grafting by varying the maleic anhydride (MA) monomer concentration ranging from 3 to 10 parts per hundred resin (phr). Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the grafting reaction of the PBSgMA. The PBSgMA was incorporated in the 80PHBHH/20PBS and 50PHBHH/50PBS blends to investigate the effect of maleated compatibilizer on the tensile, flexural, drop weight impact, and water absorption properties of the blends with droplets dispersed and co-continuous morphology. The incorporation of PBSgMA increased the tensile and flexural strength of both the 80PHBHH/20PBS and 50PHBHH/50PBS blends, where the optimum properties achieved at 5 phr concentration of MA. The drop weight impact test results showed that uncompatibilized and compatibilized 50PHBHH/50PBS blends had higher critical strain energy release rate (G_c) than the neat PHBHH. However, blending and compatibilizing did not have a positive effect on the critical stress intensity factor (K_c) of the neat PHBHH. Scanning electron microscopy (SEM) confirmed the improvement of interfacial adhesion and PBS polymer dispersion in PHBHH/PBS blends when incorporated with 5PBSgMA. The water absorption test results demonstrated that compatibilized blends absorbed slightly more water than uncompatibilized blends due to the presence of hygroscopic carboxyl groups of the PBSgMA. However, water absorption effects were reversible and did not result in severe permanent damage to the blends.     

Preparation and smoke suppression mechanism of flame-retardant PBS composites with BNNS@DOPA

Currently, the flame-retardant modification of polybutylene succinate (PBS) is mainly focused on improving flame-retardant efficiency, ignoring the negative impact of the smoke produced by combustion on the human respiratory tract. To address this problem, PBS composites were prepared by melt blending method in this study. The effect of boron nitride-grafted DOPO flame retardant (BNNS@DOPA) on flame retardancy and smoke suppression of PBS composites was investigated. Incorporating 3% BNNS@DOPA into PBS composites results in a 90% improvement in thermal conductivity. This resulted in a reduction of the peak heat release rate, total heat release rate, and actual smoke rate to 453.7 kW m⁻², 86.3 MJ m⁻², and 1035.9 m², respectively, compared with pure PBS. The latter indicated a decrease of 34.0%, 37.6%, and 51.2%, respectively. Furthermore, the ignition time was extended by 45 s and the limiting oxygen index value increased by 12.5%. This functionalization approach presents a new way to study PBS flame retardancy improvement, consequently boosting its application in fire safety for polymer materials.     

Dynamic mechanical and melt rheological properties of sulfonated poly(butylene succinate) ionomers

A series of poly(butylene succinate) ionomers (PBSi) containing 5-sodium sulfoisophthalate units were prepared by bulk polymerization of succinic acid and 1,4-butanediol in the presence of dimethyl 5-sulfoisophthalate sodium salt (DMSI) up to 5 mol% of diacid monomer. Conspicuous variation of the storage modulus for PBSi was observed, depending on the content of DMSI. The increasing rate of cluster T_g was lower compared to those of amorphous polymer-based ionomers. These results were probably due to the lower clustering ability of semi-crystalline PBSi as compared with amorphous-based ionomers. Non-contact atomic force microscopy confirmed that the size of PBSi-3 clusters was about 40∼50 nm, demonstrating that the clusters were aggregated. Melt rheological analysis was carried out to investigate the effects of ionic groups on the rheological properties as a function of temperature or shear force in the molten state. The melt viscosities of PBSi showed higher values than the parent PBS up to about 190 °C, while with further increasing temperature a falling inflection region of melt viscosity was observed. It was suggested that the relaxation of PBSi chains was due to the thermal dissociation of ionic aggregates.     

Effect of surface-modified Al2O3 on the thermomechanical properties of polybutylene succinate/Al2O3 composites

This study investigates the effect of the incorporation of alumina particles on the thermomechanical properties of polybutylene succinate (PBS)/Al₂O₃ composites. The alumina surface was modified with the carboxylic groups of maleic acid through simple acid-base and in situ polymerization reactions. Scanning electron microscope (SEM) results revealed the introduction of maleic acid treated alumina significantly affect the morphology of the PBS/Al₂O₃ composites as compared to the neat PBS. The thermal conductivity of the composite (0.411?W?m^?1 K^?1) was more than twice that of neat PBS. The composite containing polymerization-modified alumina showed a 50% increase in storage modulus compared with that of neat PBS. In addition, universal testing machine (UTM) and differential scanning calorimetry (DSC) measurements indicated an increase in the tensile strength and degree of crystallinity after the incorporation of modified alumina in the PBS/Al₂O₃ composite.     

聚丁二酸丁二醇酯/乙烯-醋酸乙烯共混物的形态与性能研究

用乙烯-醋酸乙烯橡胶（EVM）对聚丁二酸丁二醇酯（PBS）进行增韧改性,通过添加过氧化二异丙苯（DCP）使得PBS与EVM的相容性增强。结果表明,随着DCP含量的增大,PBS/EVM共混物的拉伸强度、断裂伸长率、肖氏硬度等力学性能先升高,随后又降低,其中拉伸强度由7 MPa 提高到17 MPa,100 %定伸应力由2 MPa提高到10 MPa;加入DCP使得PBS的结晶由受限结晶变为正常结晶;DCP的适宜添加量为0.3份。     

PBAT及增容剂含量对PLA/PBAT共混物结构和性能的影响

通过拉伸试验、扫描电子显微镜和差示扫描量热法分析,研究了聚己二酸-对苯二甲酸丁二酯(PBAT)用量对聚乳酸(PLA)/PBAT共混物拉伸性能、微观结构和热性能的影响。结果表明:PBAT能显著改善PLA韧性,增韧效果与PBAT相尺寸及两相间相互作用有关。当m(PLA)∶m(PBAT)=80∶20时,PLA/PBAT共混物的断裂拉伸应变提高约8倍。自制接枝共聚物增容剂能显著改善PLA与PBAT的相容性,提高两相间的相互作用。接枝共聚物增容剂最佳用量为6phr时,共混物断裂拉伸应变提高1倍多。     

Formation of polymorphic structure and its influences on properties in uniaxially stretched polybutylene terephthalate films

The evolution of structure and properties in uniaxially stretched polybutylene terephthalate (PBT) films has been explored. The stretch temperature has pronounced influences on the development of PBT polymorphism; the mechanisms of its formation involve levels of both applied stress as well as chain relaxation during the stretch period. The stretch rate, on the other hand, tends to perfect the structure. PBT films produced under different conditions develop different levels of crystallinity and orientation in the individual α and β phases, in which annealing under tension induces a partial crystal transition from the β to α phase that leads to an increment of orientation in the α phase. The mechanical behavior of the films is related to the polymorphic structure as well as to the overall chain orientation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 412–423, 2000     

PBT非等温结晶动力学

用差示扫描量热法研究聚对苯二甲酸丁二酯（PBT）的非等温结晶动力学，并分别用Ozawa,Jeziorny和考虑综合因素法来处理PBT的非等温结晶数据。结果表明，PBT非等温结晶过程与Ozawa动力学方程相吻合，但不符合用Jeziorny方法处理的Avrami动力学方程；综合考虑温度和结晶程度对聚合物结晶速度的影响。PBT非等温结晶过程符合结晶动力学方程。     

Study on the properties of nano‐TiO2/polybutylene succinate composites prepared by vane extruder

Different proportions of nanoscale TiO₂ (nano‐TiO₂)‐filled polybutylene succinate (PBS) composites were prepared by vane extruder. The crystalline, thermal, dynamic viscoelastic, mechanical, and UV‐resistance properties of the composites were studied, and X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis were conducted. Results show that the crystalline structure of the PBS composites did not change with TiO₂ addition. TiO₂ almost has no effect on the crystallization and melting behavior of PBS. Nevertheless, the introduction of TiO₂ has improved the thermal stability, tensile modulus, flexural modulus, and flexural strength of the PBS composites. The UV resistance of the composites has also been significantly enhanced with TiO₂ addition. POLYM. COMPOS., 35:53–59, 2014. © 2013 Society of Plastics Engineers