聚乳酸共混增韧和耐热性能的研究

将乙烯/甲基丙烯酸丁酯/甲基丙烯酸缩水甘油酯三元共聚物(GEBMA)和滑石粉(Talc)按不同比例加入聚乳酸(PLA)基体中,熔融共混制备PLA/GEBMA/Talc共混物。将GEBMA的质量分数固定为10%,探讨了不同含量的Talc对PLA/GEBMA/Talc共混物的力学性能、流变性能、热性能、相形态以及耐热性能的影响。结果表明:GEBMA的加入提高了PLA的韧性,冲击强度从纯PLA的4.3 kJ/m~2提高到PLA/GEBMA(90/10)的21.6 kJ/m~2。随着Talc含量的增加,PLA/GEBMA/Talc共混物的拉伸强度和冲击强度降低,弹性模量增加,PLA/GEBMA/Talc材料具有良好的力学性能。Talc起到了异相成核作用,可以提高结晶速率,减小PLA的晶体尺寸,改善了共混物的耐热性能。PLA/GEBMA/Talc材料可广泛用于可生物降解的注塑产品。     

超细滑石粉填充聚乳酸共混薄膜的制备及性能研究

采用双螺杆挤出共混法,将聚乳酸(PLA)、超细滑石粉(Talc)及乙酰柠檬酸三丁酯(ATBC)熔融共混制备生物降解粒料,并通过吹塑成型的方法制备了共混薄膜,研究了PLA共混薄膜材料的旋转扭矩、力学性能、稳定性及结晶形态。结果表明,随着超细Talc用量增加,PLA共混薄膜材料的旋转扭矩逐渐下降,拉伸强度和断裂伸长率均先增后降,直角撕裂强度基本不变;60℃体系增塑剂迁移率逐渐变小;125℃随Talc用量的增加,晶核数目增加、结晶速率增大且球晶尺寸变小。     

PLA/PHBV共混改性研究

采用熔融共混法制备了聚乳酸/聚(3-羟基丁酸-co-3-羟基戊酸酯)(PLA/PHBV)共混物,研究了PLA/PHBV质量比以及滑石粉(Talc)含量对PLA/PHBV共混物性能的影响。结果表明,随着PHBV含量的增加,PLA/PHBV的结晶度先降低后升高,断裂伸长率提高了21.81%,冲击强度提高了35.9%,拉伸强度下降;随着Talc含量的增加,PLA/PHBV/Talc的结晶度增大,冲击强度提高了12.4%,但是断裂伸长率和拉伸强度有所下降;在不显著降低拉伸强度和弯曲强度的前提下,PHBV的含量为20%(质量分数,下同)且Talc含量为1.5%时,复合材料的力学性能最优。     

无机填料对PLA树脂热稳定性影响的研究

通过熔融共混工艺制备了聚乳酸(PLA)/无机粒子复合材料。利用热失重分析(TGA)和差示扫描量热仪(DSC)探究了未改性的可回收利用的PLA和PLA/无机粒子复合材料的热性能,并对动态流变行为进行了探究。研究结果表明添加无机粒子可以提升PLA的热稳定性。滑石粉(Talc)可以诱导PLA结晶,但是SiO2和CaCO3却对结晶性能没有影响。PLA共混材料的复数黏度比纯PLA的要高。     

滑石粉与PEG的协同效应对PLA结晶性的影响

通过熔融共混的方法制备了聚乳酸(PLA)/滑石粉(Talc)/聚乙二醇(PEG)共混物,研究了共混物的非等温结晶过程,分析了PLA结晶过程中Talc和PEG的协同效应。结果表明:随着降温速率的增大,共混物的结晶峰温都向低温区偏移,结晶度降低,结晶速率提高;试验发现在成核阶段Talc起到促进晶核形成的决定性作用,Talc与PEG协同效应对PLA结晶速率的显著影响体现在生长阶段(Ⅱ区);偏光显微镜(POM)观察也表明Talc和PEG的协同效应在结晶期的生长阶段。     

UHMWPE/PLA共混体系的制备

利用熔融共混法制备了超高相对分子质量聚乙烯(UHMWPE),聚乳酸(PLA)共混体系,讨论了PLA含量对共混体系熔体流动性能、力学性能、结晶性能及吸水性能的影响.结果表明:随PLA含量的增加,UHMWPE/PLA共混体系的熔体流动性显著增强;体系收缩率下降,尺寸稳定性变好;屈服拉伸强度和缺口冲击强度下降,断裂由韧性断裂逐渐转变为脆性断裂;当w(PLA)为10%时,所制备的共混体系既能保证UHMWPE原有的缺口冲击强度和韧性断裂,又具有较好的熔体流动性能;PLA与UHMWPE共混可加快共混体系的结晶速率,使熔点下降;随着PLA含量的增加,共混体系的吸水率也随之增加.     

聚乳酸/蒙脱土纳米复合材料的制备及其热力学性能研究

采用熔融共混的方法制备了一系列聚乳酸(PLA)/蒙脱土(MMT)的纳米复合材料,通过力学性能测试、差热扫描量热仪(DSC)、熔体流动速率测试对复合材料的热性能、机械性能和流动性能进行了表征。结果表明,当MMT质量分数低于7%时,MMT对PLA有很好的增韧增强效果;当MMT的含量为5%时,复合材料的拉伸强度最好,当MMT质量分数为3%时,复合材料的冲击强度最好。当MMT质量分数低于5%时,能很好地改善PLA的流动性能,对PLA的加工成型有利。随着MMT加入,复合材料的玻璃化转变温度和熔点都比纯PLA的要低。     

无机粉体填充PBAT/PBS/PLA共混薄膜的制备与性能

将不同含量的聚丁二酸丁二酯(PBS)、碳酸钙(CaCO₃)/滑石粉(Talc)、聚乳酸(PLA)与聚对苯二甲酸-己二酸丁二酯(PBAT)进行熔融共混改性,研究各组分含量对PBAT/PBS/PLA共混材料加工性能、拉伸性能及其吹塑薄膜的拉伸性能、直角撕裂强度和热封强度的影响。采用熔体流动速率(MFR)仪、万能试验机、热封试验仪、差示扫描量热仪对PBAT共混薄膜的加工性能、力学性能和热封性能等进行测试。结合3因素3水平设计正交试验来优化试样配方,并对试验结果进行了正交试验极差分析。结果表明,PBAT/PBS/PLA共混材料的MFR值均在2.6～4.3 g/10 min范围内,薄膜吹塑成型加工稳定性良好。根据薄膜力学性能极差分析结果提出了最佳配方：PBAT含量为100质量份、PBS含量为10质量份、CaCO₃/Talc质量比为10/10和PLA含量为2质量份,验证试验结果表明,该配方制备的吹塑薄膜各项力学性能最高,横向、纵向拉伸强度分别为23.2 MPa和27.3 MPa,横向、纵向断裂伸长率分别为988%和1 137%,横向、纵向直角撕裂强度分别...     

聚乳酸/聚烯烃弹性体/蒙脱土复合材料的制备与性能研究

以聚乳酸(PLA)为基材,在聚烯烃弹性体(POE)的增塑作用下,搀杂不同比例的蒙脱土(MMT),采用熔融共混法,制备出一系列的PLA/POE/MMT复合材料。通过拉伸及冲击测试、差热扫描量热仪(DSC)、熔指仪对复合材料的力学性能、热性能和流动性能进行表征。结果表明:随着MMT的加入,PLA/POE/MMT复合材料的拉伸性能和冲击性能总体上比纯PLA差,复合材料的玻璃化转变温度(Tg)和熔点(Tm)总体上比纯PLA要低,只有当MMT含量为1 wt.%时,才使PLA体系的冲击强度有所提高,Tg和Tm有所提高。随着MMT的加入,PLA体系的流动性变好。     

天然橡胶和纤维素纳米晶对聚乳酸的共混改性研究

通过在天然橡胶(NR)分子链上接枝丙烯酸丁酯(BA)制备接枝改性物NR-g-PBA,并将NR-g-PBA以及NRg-PBA和纤维素纳米晶(CNC)分别与聚乳酸(PLA)熔融共混,得到PLA/NR-g-PBA二元共混物和PLA/NR-g-PBA/CNC三元共混物。研究NR-g-PBA和CNC对共混物力学性能、结晶性能和热稳定性的影响。结果表明:与PLA相比,PLA/NR-g-PBA二元共混物的韧性提高,但拉伸强度降低;随着CNC用量增大,PLA/NR-g-PBA/CNC三元共混物的拉伸强度和拉断伸长率均呈先提高后降低趋势,PLA/NR-g-PBA/CNC共混物(CNC相对于PLA的质量分数为0. 005)的拉伸强度最高,PLA/NR-g-PBA/CNC共混物(CNC相对于PLA的质量分数为0. 01)的拉断伸长率最高;PLA/NR-g-PBA二元共混物和PLA/NR-g-PBA/CNC三元共混物的结晶温度和结晶度均比纯PLA有所提高;NR-g-PBA和CNC的引入有助于提高PLA的热稳定性。     

PBAT复合材料的改性研究进展

综述了近年来国内外可降解高分子材料(如聚羟基丁酸戊酸共聚酯、聚碳酸亚丙酯、聚丁二酸丁二酯和聚乳酸),天然高分子材料(如淀粉、纤维素和木质素),无机填充物(如蒙脱土、有机黏土、碳纳米管和碳酸钙),以及扩链剂等对聚己二酸-对苯二甲酸丁二酯(PBAT)复合材料的改性研究进展。通过熔融共混改性,复合材料的力学性能、热性能、熔体黏度和尺寸稳定性有了很大提高。最后对PBAT未来的研究进行了展望。     

Non‐Isothermal Crystallization Behavior of Poly(L‐lactic acid) in the Presence of Various Additives

Summary: The effects of various additives: poly(D ‐lactic acid) (PDLA), talc, fullerene C₆₀, montmorillonite, and various polysaccharides, on the non‐isothermal crystallization behavior of poly(L ‐lactic acid) (PLLA), during both the heating of melt‐quenched films from room temperature, and the cooling of as‐cast films from the melt, was investigated. When the melt‐quenched PLLA films were heated from room temperature, the overall PLLA crystallization was accelerated upon addition of PDLA or the stereocomplex crystallites formed between PDLA and PLLA, the mixtures containing PDLA, and the mixture of talc and montmorillonite. No significant effects on the overall PLLA crystallization were observed for talc, C₆₀, montmorillonite, and the mixtures containing C₆₀. Such rapid completion of the overall PLLA crystallization upon addition of the aforementioned additives can be ascribed to the increased density (number per unit volume or area) of PLLA spherulites. When the as‐cast PLLA films were cooled from the melt, the overall PLLA crystallization completed rapidly, upon addition of PDLA, talc, C₆₀, montmorillonite, and their mixtures. Such rapid overall PLLA crystallization is attributable to the increased density of the PLLA spherulites and the higher nucleation temperature for PLLA crystallization. In contrast, the addition of various polysaccharides has no significant effect, or only a very small effect, on the overall PLLA crystallization during heating from room temperature or during cooling from the melt. This finding means that the polysaccharides can be utilized as low‐cost fillers for PLLA‐based materials, without disturbing the crystallization of the PLLA. The effect of additives in accelerating the overall PLLA crystallization during cooling from the melt, decreased in the following order: PDLA > talc > C₆₀ > montmorillonite > polysaccharides.

Polarization optical photomicrographs of pure PLLA, and the PLLA‐F film, with the fullerene additive, during cooling from the melt (Process IIB). Both of the photomicrographs were taken at 120 °C.     

可降解聚乳酸复合材料研究进展

对聚乳酸（PLA）复合材料的生物降解性能进行综述,总结PLA与有机物（如木质素、纤维素等）、无机物（如碳酸钙、纳米银颗粒等）复合后力学性能、热性能、生物相容性、抗菌性的变化及在不同环境条件下生物降解速率的变化,梳理了PLA复合材料结构、组成与降解性能的相互关系,对降解性能可控的PLA复合材料应用前景进行了展望。     

Talc as a nucleating agent and reinforcing filler in poly(lactic acid) composites

The effect of talc on the crystallinity and mechanical properties of a series of poly(lactic acid) (PLA)/talc composites has been investigated. The composites were prepared by melt blending followed by compression molding. It was found that talc acted as a nucleating agent and increased the crystallinity of the PLA from 2% to 25%. There was significant improvement in Young's modulus of the composites with increasing talc addition and these results were found to fit the Halpin Tsai model. Thermo‐mechanical tests confirmed that the combination of increased crystallinity and storage modulus leads to improvement in the heat distortion properties. POLYM. ENG. SCI., 54:64–70, 2014. © 2013 Society of Plastics Engineers     

Mechanical,barrier, and thermal properties of poly(lactic acid)/poly(trimethylene carbonate)/talc composite films

Poly(l ‐lactic acid) (PLA) is now a very attractive polymer for food packaging applications. In this study, PLA/poly(trimethylene carbonate) (PTMC)/talc composite films were prepared by solvent casting. The influence of the talc loading (0, 1, 2, and 3 wt %) on the phase morphology of the PLA/PTMC/talc composites and the improvement in the resulting properties are reported in this article. The scanning electron microscopy images of the composite films demonstrated good compatibility between the PLA and PTMC, whereas talc was not thoroughly distributed in the PLA matrix at talc contents exceeding 3 wt %. The tensile strength and elongation at break of the composite films significantly improved (p < 0.05). On the contrary, the water vapor permeability and oxygen properties of the composite films decreased by 24.7 and 39.2%, respectively, at the 2 wt % talc loading. Differential scanning calorimetry showed that the crystallinity of the PLA phase increased with the presence of talc filler in the PLA/PTMC/talc composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40016.     

Evolution of the mechanical properties and estimation of the useful lifespan of poly(lactic acid) based compounds

The useful lifespans of a poly(lactic acid)/poly(methyl methacrylate) (PLA/PMMA) 80/20 (wt%) blend and a poly(lactic acid)/dioctyl adipate/talc (PLA/DOA/talc) compound have been estimated by applying an Arrhenius relationship to the evolution of the mechanical properties whilst ageing. The studied PLA based systems showed lower activation energies (ca 8 ? 20 kJ mol^?1) than those reported in the literature for other synthetic thermoplastics, indicating lower thermo‐oxidative stability. However, both systems were interesting choices for semi‐durable applications in terms of useful lifespan estimations. The PLA/PMMA blend showed a drastic loss in stiffness at T_g due to its almost amorphous structure whereas, in contrast, PLA/DOA/talc showed acceptable mechanical properties above its glass transition temperature due to its semicrystalline structure. © 2018 Society of Chemical Industry     

Synergistic effects of N,N′‐bis (benzoyl) sebacic acid dihydrazide and talc on the physical and mechanical behaviors of poly(l‐latic acid)

The important practical problem of poor heat stability of poly(l ‐lactic acid) (PLLA) is addressed by the addition of N, N′‐bis (benzoyl) sebacic acid dihydrazide (BSAD) and talc as a nucleating agent system. The idea of incorporating talc into the PLLA/BSAD composites is that talc can provide supplementary nucleation effect with very small amount of BSAD (0.2 wt %) and therefore can improve the heat deflection resistance of PLLA materials. Effects of BSAD/talc on morphology, crystallization behavior, heat resistance, and mechanical properties of PLLA/BSAD/talc were investigated after annealing processes. The results indicated that the BSAD/talc system increased the crystallinity from 6.0% of pure PLLA to a maximum 42.9% by the synergistic effects of BSAD and talc increasing the growth of spherulites and nucleation density, respectively. After annealing at different temperatures, the heat deflection temperature (HDT) of PLLA was improved dramatically due to synergistic effects of BSAD/talc between restricted chain movement and acceleration of crystallization. At high temperature (above T_g), the thermo‐mechanical properties of PLLA is mainly determined by the crystallinity and the reinforcement effect of talc acted as a filler. Moreover, effects of BSAD/talc on mechanical properties were discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41454.     

Effect of biobased and biodegradable nucleating agent on the isothermal crystallization of poly(lactic acid)

The effect of chemically modified thermoplastic starch (CMPS) on the thermal properties and isothermal crystallization kinetics of poly(lactic acid) (PLA) was studied by differential scanning calorimetry (DSC) and compared to that of granular starch and an inorganic nucleating agent, talc. Nucleated PLA showed an additional crystallization of PLA, which affected the melting temperature. The crystallinity and crystallization rate of PLA were considerably enhanced by addition of CMPS, even at 0.1% content, and the amount of the CMPS had little effect on the thermal properties and isothermal crystallization kinetics of PLA. The effect of CMPS as a nucleating agent was comparable to that of granular starch but slightly less than that of talc. However, CMPS can offer a fully biodegradable nucleating agent with no residues remaining for the biobased and biodegradable polymers.     

Thermal–mechanical property and fracture behaviour of plasticised PLA–CaCO3 nanocomposite

Abstract

This study investigates the influence of two plasticisers, polyethylene glycol (PEG) and tributyl citrate (TbC), on the thermomechanical properties and fracture behaviour of nanosized calcium carbonate blended poly(lactic acid). Various compositions of nanocomposites were compounded and processed using co-rotating twin screw extrusion and compression moulding. DMA analysis shows that adding nano-CaCO₃ reduced the storage modulus (E′) of the nanocomposite while the glass transition temperature (T_g) of the samples was not affected. Furthermore, plasticised poly(lactic acid) (PLA) showed an improvement in elongation at break in all samples, and the impact resistance of the nanocomposites was also improved by 1·6 times with the addition of 20 phr PEG plasticiser and by 1·4 times with the addition of 20 phr TbC plasticiser. Morphological study reveals that the fracture behaviour of PLA-CaCO₃ nanocomposites changed from brittle to ductile after plasticisers were incorporated.     

改性矿物填料增强橡胶/聚氯乙烯共混体系

研究了橡胶、增塑剂、矿物填料和表面处理剂对橡胶／聚氯乙烯(PVC)共混物力学性能的影响,用扫描电镜分析了有机胺类表面处理剂改性高岭土／丁腈橡胶(NBR)／PVC的界面结合状况。结果表明,当NBR用量为30份,邻苯二甲酸二辛酯用量为60份,有机胺类表面处理剂质量分数为3％,填充60份的超细碳酸钙或高岭土或牌号为SMF的蒙脱土时,可得到力学性能较佳的NBR／PVC共混物;不同矿物填料对NBR／PVC共混物的增强作用不同,经有机胺类表面处理剂改性后,以超细碳酸钙、高岭土和蒙脱土SMF的增强效果最为明显。