EVA熔体流动速率对PLA/EVA共混物性能的影响

通过熔融共混法制备了聚乳酸（PLA）/乙烯-乙酸乙烯酯共聚物（EVA）共混物,采用SEM、DSC、旋转流变仪等研究了VA质量分数为28%,熔体流动速率（MFR）不同的EVA对PLA/EVA共混物性能的影响。结果表明,EVA熔体流动速率越小,其在PLA基体中分散越均匀,EVA颗粒粒径也越小。共混物的结晶度随EVA熔体流动速率的增大而增大,但PLA的玻璃化转变温度（Tg）基本不受EVA的影响。PLA/EVA共混物的复数黏度和储能模量均随EVA的熔体流动速率的增高而减小。力学性能测试结果表明,当EVA的质量分数为15%时,PLA的断裂伸长率明显升高,冲击强度约是纯PLA的2倍。     

Comparison of sorbitol and glycerol as plasticizers for thermoplastic starch in TPS/PLA blends

This article investigates the structure and properties of thermoplastic starch/PLA blends where the TPS phase is plasticized by sorbitol, glycerol, and glycerol/sorbitol mixtures. The blends were prepared using a twin‐screw extruder where starch gelatinization, water removal, and dispersion of TPS into a PLA matrix were carried out sequentially. The plasticizers were added to starch in the first stage of the extruder to allow complete starch gelatinization. The PLA was added at mid‐extruder and thoroughly mixed with the TPS. The plasticizer concentration was varied from 30 to 42% and the TPS content was varied from 27 to 60% on a weight basis. In all investigated blends, the PLA formed the continuous phase and the TPS was the dispersed phase. The viscosity, blend morphology, tensile mechanical properties as well as the thermal properties of the materials were measured. It was found that the glycerol/sorbitol ratio has an important effect on the blend properties. Finer blend morphologies, higher tensile strength and modulus but lower crystallization rate were found for the sorbitol plasticized blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

BR/EVA TPV的制备及性能研究

采用动态硫化法制备BR/乙烯-乙酸乙烯酯共聚物(EVA)热塑性硫化胶(TPV),并对其性能进行研究.结果表明:当BR/EVA共混比大于50/50时,TPV呈现出典型弹性体的应力-应变行为;当BR/EVA共混比为50/50～65/35时,TPV的硬度较低,综合物理性能良好;当BR/EVA共混比为60/40时,微米级的BR粒状物均匀分散在EVA基体中,两相界面结合良好.     

Preparation and characterization of thermoplastic starch/PLA blends by one‐step reactive extrusion

In the presence of dicumyl peroxide, the compatibility of thermoplastic dry starch (DTPS)/poly(lactic acid) (PLA) blends, using maleic anhydride (MA) as compatibilizer, was investigated. The plasticization of starch and its compatibilizing modification with PLA was accomplished in a single‐screw extruder by one‐step reactive extrusion. In the presence of MA, the plasticization of starch in DTPS/PLA blends could be improved and homogeneous DTPS/PLA blends could be achieved as observed using scanning electron microscopy. Tensile tests showed that the tensile strength of compatibilized DTPS/PLA blends was about 40.5 MPa higher than that of the original composites. Differential thermal analysis indicated that the glass transition temperature of DTPS and PLA became closer in the presence of MA than the blend without any additions, which suggested the compatibility between DTPS and PLA was improved. In addition, Fourier transform infrared spectroscopy proved that MA improved the interaction between DTPS and PLA. At the same time, the blend became more thermally stable as shown by thermogravimetric analysis results. A novel decomposition peak at about 450 °C was detected in the compatibilized blend, which was higher than those observed for DTPS and PLA. Finally, a rheological study suggested that MA could improve the fluidity of DTPS/PLA blends. Copyright © 2007 Society of Chemical Industry     

PLA/PBS共混物的动态流变性能

研究聚丁二酸丁二酯(PBS)对聚乳酸(PLA)流变性能的影响。通过熔融挤出的方法在双螺杆挤出机上制备PLA/PBS共混物,采用旋转流变仪研究PLA/PBS共混物的动态流变性能。结果表明,当应变为6%时,PLA/PBS共混物的储能模量和损耗模量随着角频率的增加而增大,而PLA/PBS共混物的损耗因子和复数黏度随着角频率的增加而降低,共混物熔体表现出剪切变稀现象。用Han方法分析表明,共混物没有发生明显的相分离现象。动态时间扫描表明,时间对于纯PLA的储能模量没有影响,但是对于PLA/PBS共混物的储能模量有较大的影响。     

Studies on polymer blends with moderate specific interactions. 2. phase structure of blends SAN/TPU and SAN/TPU/EVA

This paper deals with morphological studies of binary and ternary blends composed of poly(styrene-co-acrylonitrile) (SAN), polyurethane elastomer (TPU) and poly(ethylene-co-vinyl acetate) (EVA). Selective etching was found necessary to expose the morphologies of the blends. Chloroform or hot acetone, hexane/toluene (2/1v/v) and NaOH/CH₃OH (1wt%) were found to be selective etching agents for SAN, EVA and TPU, respectively. SAN and TPU form blends with fine dispersion structure, while SAN and EVA lead to rough phase structure with poor phase adhesion. These results are in accordance with the difference in the mechanical properties of SAN/TPU and SAN/EVA. In addition, for SAN/TPU/EVA blends, if TPU is only a minor component, it is preferentially located at the interphase, playing the role of a compatibilizer. As the amount of TPU increases, the compatibility is gradually improved. ©1997 SCI     

邻苯二甲酸二辛酯对PLA／EVA共混物性能的影响

研究了增塑剂邻苯二甲酸二辛酯（DOP）对聚乳酸／乙烯-醋酸乙烯酯弹性体（PLA／EVA）共混物力学、热学和结晶性能的影响。结果表明：PLA／DOP（100／20）共混物的缺口冲击强度、无缺口冲击强度及断裂伸长率比纯PLA分别提高了183％、197％和667％，共混物中PLA的玻璃化转变温度和熔融温度分别降低21．0℃和18．3℃，结晶度提高42％；PLA／EVA／DOP（80／20／8）的缺口冲击强度、无缺口冲击强度及断裂伸长率比PLA／EVA（80／20）分别提高了47％、57％和148％，共混物中PLA的玻璃化转变温度和熔融温度分别降低90℃和11.5℃，结晶度提高11％；DOP的加入会使EVA粒子在PLA中的分散度和均一性更佳。     

The morphology,rheological, and mechanical properties of wood flour/starch/poly(lactic acid) blends

An entirely biosourced blend composed of poly(lactic acid) (PLA), starch, and wood flour (WF) was prepared by a co‐extruder with glycerol as a plasticizer. The morphology, rheological properties, and mechanical properties of the WF/starch/PLA blends were comprehensively analyzed. The results showed that with the decrease of the starch/WF ratio, the morphology experienced a large transformation, and the compatibility of the blends was found to be superior to other blends, with a starch/wood flour ratio of 7/3. The dynamic mechanical thermal analysis (DMA) results demonstrated the incompatibility of the components in WF/starch/PLA blends. Following the decrease of the starch/WF ratio, the storage modulus (G″) and the complex viscosity (η*) of the blends increased. The mechanical strength first increased, and then decreased with the increase of the WF concentration. The water absorption results showed that the water resistance of the blends was reduced with the lower starch/WF ratio. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44743.     

动态交联PP/EVA共混物的制备与性能研究

本文将动态交联技术应用于PP/EVA共混体系中,制得动态交联PP/EVA共混物。采用Hakke转矩流变仪研究了动态交联对PP/EVA共混物扭矩的影响;研究了DCP和EVA含量对共混物力学性能的影响;考察了动态交联共混物的维卡软化点。结果表明：加入DCP后,PP/EVA共混物扭矩先升后降,DCP的添加量为EVA含量的1%为宜。随EVA用量的增加,动态交联EVA/PP共混物的冲击强度大幅提高,但拉伸强度有所降低。少量经动态交联的EVA颗粒可以促进共混物中PP的结晶, 提高共混物的维卡软化点。     

Biodegradable polymer blends of poly(lactic acid) and poly(ethylene glycol)

Poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were melt-blended and extruded into films in the PLA/PEG ratios of 100/0, 90/10, 70/30, 50/50, and 30/70. It was concluded from the differential scanning calorimetry and dynamic mechanical analysis results that PLA/PEG blends range from miscible to partially miscible, depending on the concentration. Below 50% PEG content the PEG plasticized the PLA, yielding higher elongations and lower modulus values. Above 50% PEG content the blend morphology was driven by the increasing crystallinity of PEG, resulting in an increase in modulus and a corresponding decrease in elongation at break. The tensile strength was found to decrease in a linear fashion with increasing PEG content. Results obtained from enzymatic degradation show that the weight loss for all of the blends was significantly greater than that for the pure PLA. When the PEG content was 30% or lower, weight loss was found to be primarily due to enzymatic degradation of the PLA. Above 30% PEG content, the weight loss was found to be mainly due to the dissolution of PEG. During hydrolytic degradation, for PLA/PEG blends up to 30% PEG, weight loss occurs as a combination of degradation of PLA and dissolution of PEG. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1495–1505, 1997     

PLA/PBAT共混物的降解性能研究

通过双螺杆挤出机和吹膜机组制备不同比例的聚乳酸/聚对苯二甲酸己二酸丁二酯（PLA/PBAT）共混物薄膜,测量共混物的热性能、力学性能,并观察其相形貌,计算共混物在堆肥条件下的生物降解率,研究共混物降解前后的结构、热力学行为和元素的变化。结果表明,PLA与PBAT是不相容体系,加入PBAT后PLA的韧性得到改善;PLA的生物降解率高于PBAT,共混物的生物降解率随着PBAT含量的增加而降低,且在降解初期,PLA的降解产物会促进PBAT的水解;PLA、PBAT及其共混物在堆肥降解前期只是大分子链水解为小分子链的过程,不发生分子链的结构变化;PLA及PBAT的降解会先发生在无定形区,共混物中PLA在无定形区的降解速度受到PBAT的影响而变慢,且共混物中PLA、PBAT的降解行为发生变化,无定形区与结晶区的降解同时发生;共混物在堆肥试验初期的降解以水解为主。     

PLA/POE-g-GMA共混物的制备及性能研究

采用熔融反应法制备乙烯-辛烯共聚物（POE）接枝甲基丙烯酸缩水甘油酯（GMA）（POE-g-GMA）,实现POE反应的官能化,通过反应共混的方法制备聚乳酸（PLA）/POE共混物,考察了POE和POE-g-GMA对PLA的力学性能和热性能及微观形态的影响。结果表明：POE-g-GMA要有适当的接枝率,增韧效果才显著,用0.6%～0.8%接枝率的POE-g-GMA增韧PLA,当POE-g-GMA质量分数达到20%时,共混物的缺口冲击强度提高到基体PLA的6倍左右;同时材料的热性能基本不受影响。POE与PLA间相容性不好,接枝后与PLA间相容性得到改善。     

聚乳酸（PLA）／己二酸-对苯二甲酸-丁二酯共聚物（PBAT）／乙酰化柠檬酸三丁酯（ATBC）共混物的结晶行为

采用熔融共混法制备聚乳酸（PLA）／己二酸-对苯二甲酸-丁二酯共聚物（PBAT）／乙酰化柠檬酸三丁酯（ATBC）共混物。用差示扫描量热仪（DSC）和偏光显微镜（POM）分析了乙酰化柠檬酸三丁酯（ATBC）对共混物PLA结晶行为的影响。结果表明当PLA／PBAT含量为80／20（质量比）时,随着ATBC量的增加,PLA的Tg、Tc和Tm降低,结晶度提高,球晶生长速率增加。     

HIPS/EVA/CB体系的相容性

研究了炭黑(CB)对高抗冲聚苯乙烯(HIPS)/乙烯-乙酸乙烯酯共聚物(EVA)共混体系相容性的影响,并预测了共混体系的相形态转变点。填充CB后,当EVA用量大于50 phr时,碳氧双键伸缩振动峰的位置由1 737.9cm~(-1)偏移到1 706.5 cm~(-1)附近,且在1 240.0 cm~(-1)附近的碳氧单键峰减弱,近乎消失。采用半经验公式对共混体系进行理论预测,HIPS/EVA/CB共混体系理论上发生相形态转变时,HIPS的临界质量分数为50%～60%,经傅里叶变换红外光谱和扫描电子显微镜照片分析,共混体系发生相形态转变时,HIPS的质量分数约为42%。     

吹膜级PBS/PLA复合材料的制备与性能研究

利用熔融共混法制备了综合性能优良的吹膜级聚丁二酸丁二酯/聚乳酸(PBS/PLA)复合材料,并通过万能试验机、差示扫描量热分析仪、热重分析仪、透气透湿分析仪分别测试了PBS/PLA复合材料及其薄膜的力学性能、热性能、阻隔性能。结果表明,制备的PBS/PLA复合材料较纯PBS树脂具有更好的刚性,且所吹塑的薄膜与包装用低密度聚乙烯膜各项性能相当。     

Electrically conductive,melt-processed polyaniline/EVA blends

Mechanical blends of ethylene–vinyl acetate copolymer and polyaniline doped with dodecyl benzene sulfonic acid (PAni–DBSA) were prepared in a two-roll mill at 50°C and in a Haake internal mixer at 150°C. The effects of the blend composition and processing conditions on the electrical conductivity and mechanical properties were investigated. These blends exhibited high levels of electrical conductivity at a small amount of PAni complex. Blends prepared in a two-roll mill displayed conductivity values as high as 1 S/cm and a higher protonation degree than the pure PAni–DBSA, as indicated by X-ray photoelectron spectroscopy. Two different insulator–conductor transition points were observed in these blends. The mechanical performance decreased as the amount of PAni–DBSA increased, indicating blend incompatibility and a plasticizing effect of the DBSA. The morphology of the blends were studied by scanning electron microscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 114–123, 2001     

不同分子量PCL增韧PLA的结构与性能

采用两种不同分子量的聚(ε-己内酯)(PCL)(粘均分子量60 000和3 000)与聚乳酸(PLA)在175℃下共混10 min制备PLA/PCL共混物。通过动态流变、扫描电子显微镜(SEM)和力学性能等研究了PLA/PCL共混物的结构和性能。动态流变显示,在PCL低含量(质量分数小于15%)时,PCL与PLA是相容的,质量分数为15%时PCL与PLA表现出明显的相分离行为。SEM显示,随着PCL含量的增加,PCL相的尺寸变大;低分子量PCL(L-PCL)的相尺寸明显大于高分子量PCL(H-PCL),而且相形态不是规则的球状。随着PCL含量的增加,共混物的拉伸强度下降,而断裂伸长率增加。当H-PCL质量分数为8.3%时,PLA/H-PCL共混物的断裂伸长率为137.32%。当H-PCL质量分数为15%时,其断裂伸长率高达232.76%。在添加相同含量PCL时,PLA/H-PCL共混物的拉伸强度高于PLA/L-PCL;而PCL质量分数8%时,共混物的断裂伸长率相差不多,当PCL质量分数大于8%时,PLA/H-PCL共混物的断裂伸长率明显比PLA/L-PCL共混物的高。     

EVA增容HDPE/PLA共混体系的研究

以乙烯-醋酸乙烯共聚物(EVA)为增容剂,采用熔融共混法制备了高密度聚乙烯(HDPE)/聚乳酸(PLA)/EVA复合材料,研究了EVA用量对复合材料力学性能及热性能的影响,并利用扫描电镜分析了复合材料的微观形态。结果表明:随着EVA用量的增加,复合材料的断裂伸长率及冲击强度逐渐增加;另外SEM结果显示,EVA可以改善HDPE与PLA的相容性,但EVA的加入对复合材料热性能影响较小。     

PET/PLA共混物相容性和结晶性能的研究

研究了相容剂钛酸四丁酯[Ti(OBu)4]含量、聚乳酸(PLA)含量对聚对苯二甲酸乙二醇酯(PET)/PLA共混物相容性的影响,探讨了共混物的熔融和结晶行为,并对其结晶形貌进行了观察。结果表明,Ti(OBu)4含量为PLA的4%(质量分数,下同)时,PET/PLA共混物的相容性良好,但当PLA含量超过30%时,共混物出现相分离;PLA的加入使PET的结晶峰变窄,结晶速率增加,且结晶峰温度向高温方向移动;PLA的加入使PET的晶粒尺寸大幅减小,晶粒数目大幅增加,结晶更加完善。     

PBAT/PLA薄膜的制备及性能研究

将聚乳酸（PLA）和聚对苯二甲酸-己二酸-丁二醇酯（PBAT）共混制备成共混材料,探讨了不同PLA含量对材料性能的影响。结果表明,PBAT/PLA共混材料中,随着PLA含量的增加,拉伸强度先降低后升高,当PLA含量为90 %时,拉伸强度达到60.12 MPa,而其断裂伸长率从703 %降低至8 %,由韧性材料逐渐转变为脆性材料;PLA含量为30 %时,性能变化出现拐点;PLA含量为50 %时出现明显相分离,且PLA的加入可以加速PBAT材料的结晶,使结晶温度由38 ℃提高至82 ℃;PBAT/PLA共混材料在PLA含量低于70 %时,都可以实现较好的吹膜过程,且薄膜材料的拉伸强度为39.59 MPa,断裂伸长率不低于137 %。