抑菌型可降解PLA/PCL/T-ZnOw形状记忆复合材料的制备与性能研究

采用溶液共混法制备聚乳酸/聚己内酯(PLA/PCL)复合材料,研究了四针状氧化锌晶须(T-ZnOw)对PLA/PCL复合材料的力学性能、形状记忆性能、热稳定性及降解性的影响。结果表明,当PCL质量分数为30%,T-ZnOw质量分数为3%时,PLA/PCL/T-ZnOw复合材料的拉伸强度和断裂伸长率较分别提高了40.8%、74.1%,形状记忆性能达到最佳。T-ZnOw赋予了PLA/PCL复合材料一定的抑菌性,同时还促进了复合材料的降解。PLA/PCL/T-ZnOw复合材料较PLA/PCL复合材料的结晶度(X_C)提高了,形状记忆的固定率明显增加;初始热分解温度降低,残炭量提高。这种具有抑菌性的可降解PLA/PCL/T-ZnOw形状记忆材料在医疗和智能材料领域将有广泛的应用前景。     

吸附材料与聚乳酸共混制备可降解材料及其除磷效果对比

制备了聚乳酸(PLA)/CeO_2和PLA/Al(OH)_3可降解吸附材料,研究了溶液pH值、温度和共存离子种类对两种复合材料吸附除磷效果的影响。结果表明:PLA/Al(OH)_3材料较PLA/CeO_2材料吸附除磷的能力更强;在酸性条件下,PLA/Al(OH)_3复合材料具有较强的吸附能力,其吸附量可以达到40 mg/g;温度对PLA/Al(OH)_3材料吸附效果影响不大;随着共存离子浓度的升高,Ca~(2+)及Mg~(2+)的存在显著提高对磷的吸附能力,阴离子的存在几乎不影响PLA/Al(OH)_3材料对磷的吸附。透射电子显微镜(TEM)分析表明,PLA/Al(OH)_3复合材料主要为超细的絮状物,其粒径很小且结构疏松,在吸附除磷方面具有良好的应用前景。     

表面改性剂和硅油对HDPE/Al(OH)3力学性能的影响

探讨了各种表面改性剂和硅油对高填充HDPE/Al（OH)3复合材料力学性能的影响。研究表明,使用经特殊表面改性剂处理的Al（OH)3作填料并加入硅油时,可以大幅度提高HDPE/Al（OH)3复合材料的缺口冲击强度和断裂伸长率。利用扫描电镜和差示扫描量热仪研究了Al（OH)3的表面改性对硅油分布的影响,观察到硅油的两种分布类型;包覆Al(OH）3粒子和以液滴形式与Al(OH）3粒子单独分散于HDPE中,并将硅油的分布状况与材料的力学性能作了对比分析。     

PCL增韧PLA材料的流变行为及其热降解动力学

针对聚乳酸(PLA)的自身结晶速率慢而导致其韧性和耐热性差等缺陷,采用聚己内酯(PCL)与PLA熔融共混制备了PLA/PCL材料,并对其力学性能、热稳定性、流变等性能进行了研究。结果表明:PCL的添加量为5%时,PLA共混材料的断裂伸长率可达18.47%,冲击强度可达12.98 kJ/m~2;断面扫描显示,PCL增韧PLA复合材料出现了明显的韧性断裂特征,出现了更多的剪切区域和拉丝现象;DSC表明,PLA的冷结晶峰受到抑制,结晶速率明显提高,复合材料的结晶度比纯聚乳酸提高了73.4%,聚乳酸的韧性得到显著提高。同时,通过热降解动力学分析,进一步从理论上分析其热稳定性能提高的原因。     

原位形成FPP偶联Al(OH)3/PP中的界面相互作用研究

制备低含量Al(OH)3填充PP复合材料[Al(OH)3/PP]，研究原位形成的官能团化聚丙烯（FPP）在Al(OH)3/PP中的结晶、熔融行为，结晶形态，以及与各组分间的相互作用。研究认为，在复合材料中存在Al(OH)3与FPP间的化学作用，FPP与PP的相容与共结晶作用，Al(OH)3表面异相诱导成核作用，FPP对Al(OH)3表面异相诱导成核作用的活化作用等，从而改善了Al(OH)3/PP的物理与力学性能。     

纳米HA对PLA/PCL复合材料降解性能的影响

以聚乳酸(PLA)为基体,添加聚己内酯(PCL)以及羟基磷灰石(HA)熔融共混得到PLA/PCL/HA复合材料,研究其力学性能与降解性能。结果表明,当材料配方为PLA80/PCL20/HA5时,复合材料的综合力学性能最好,断裂伸长率从5%提升至40%;通过差示扫描量热仪(DSC)测试了复合材料的结晶性能,HA的加入起到异位成核点的作用,结晶度从2.6%提升至8.9%,玻璃化转变温度从60.13℃降至56.84℃,扫描电镜(SEM)观察了复合材料的界面相容度,发现HA的加入提升了PLA与PCL的相容度;通过水解降解过程中的pH值测试与三维超景深显微镜观察得知,由于HA在水解过程中溶解脱落,使得复合材料整体被破坏,水解速率快于纯聚乳酸。     

超细Al(OH)3对PP球晶结构和性能的影响

分别用超细Al(OH)_3和普通Al(OH)_3填充聚丙烯(PP),研究了超细Al(OH)_3/PP和普通Al(OH)_3/PP体系的力学性能、熔体流动性、阻燃性能及其结晶的微观形态。结果表明,加入适量的超细Al(OH)_3对PP具有增韧效应;超细Al(OH)_3能使PP球晶显著细化;与普通Al(OH)3/PP相比,超细Al(OH)_3/PP具有较好的抗冲击性能、拉伸性能和弯曲性能,但熔体流动性低。     

氢氧化铝高填充聚乙烯材料的界面和力学性能

从Al(OH)3高填充线型低密度聚乙烯（LLDPE）材料的界面性质出发,研究了复合材料界面改性与硅烷交联方法对LLDPE/Al(OH)3复合材料的微观结构,加工流动性及力学性能的影响。钛酸酯和乙烯-醋酸乙烯共聚物能显著改善LLDPE/Al(OH)3复合材料的延伸性能,硅烷交联与界面改性对改善材料的力学性能具有协同作用。     

油酸表面修饰对竹粉/聚己内酯复合材料力学性能的影响

以油酸(OA)作为表面活性剂,包覆在碱处理过的竹粉(BF)表面。再将聚己内酯(PCL)与油酸包覆的竹粉(OA-BF)熔融共混,通过热压成型制得了竹粉填充聚己内酯复合材料(OA-BF/PCL)。使用傅里叶红外光谱(FTIR)、热失重分析仪(TG)、扫描电子显微镜(SEM)、万能力学试验机、示差扫描量热仪(DSC)等分析仪器对OA-BF/PCL复合材料进行表征,研究OA-BF/PCL复合材料的微观结构、力学性能和非等温结晶行为。结果表明,OA的修饰提高了BF的热稳定性;OA-BF与PCL基体之间相容性好,界面结合紧密;OA-BF/PCL复合材料的拉伸强度和冲击强度在OA-BF质量分数为5%时分别提升了15%、16%,而拉伸模量与填充量成正比,提升了58%。且适量的OA-BF能够促进PCL结晶,相比纯PCL的结晶度提升了1.3倍。     

PLA/PCL纳米复合材料研究进展

综述了近年来聚乳酸(PLA)/聚己内酯(PCL)纳米复合材料的研究进展,重点介绍了PLA/PCL/碳纳米管、PLA/PCL/石墨烯、PLA/PCL/有机改性蒙脱土、PLA/PCL/埃洛石纳米管、PLA/PCL/纳米二氧化钛、PLA/PCL/羟基磷灰石,以及PLA/PCL/天然高分子等纳米复合材料的制备和性能.分析表明,...     

Crystallization,mechanical properties,and enzymatic degradation of biodegradable poly(ε‐caprolactone) composites with poly(lactic acid) fibers

Biodegradable polymer composites based on poly(ɛ‐caprolactone) (PCL) and poly(lactic acid) (PLA) fibers were prepared by melt compounding. The effects of PLA fibers on the crystallization, mechanical properties, and enzymatic degradation of PCL composites were investigated. The addition of PLA fibers enhanced the crystallization of PCL due to the heterogeneous nucleation effect of fibers. However, the final crystallinity of the PCL in the composites was little changed in the presence of PLA fibers. With the addition of PLA fibers, significant improvement in storage modulus (E′) of PCL in the composites was achieved. A significant increase in E′ was 173% for the composites as compared to that of the neat PCL at 20°C. With the increase in PLA fibers content, the PCL composites showed decreased elongation and strength at break; however, the tensile yield strength and modulus were increased significantly, indicating that PCL was obviously reinforced by adding PLA fibers. Although the PLA fibers retarded the enzymatic degradation of PCL, it was possible to be completely degraded without much degradation time for PCL blending with suitable amounts of PLA fibers. POLYM. COMPOS., 34:1745–1752, 2013. © 2013 Society of Plastics Engineers     

PLA/PCL/滑石粉复合材料的制备与性能

在聚乳酸(PLA)中添加不同含量的聚己内酯(PCL)和滑石粉,同时添加增容剂柠檬酸三丁酯(TBC),通过熔融共混制备一系列PLA/PCL/滑石粉复合材料。主要研究了PCL、滑石粉以及TBC对PLA力学性能和结晶性能的影响。结果表明,PCL提高了PLA的韧性,但降低了强度,滑石粉主要起到了增强作用,但降低了PLA韧性,而将两者共同添加到PLA中可以起到一定的增强增韧作用,其异相成核作用也提高了PLA的结晶度。增容剂TBC的加入,改善了PLA和PCL的相容性,提高PCL的增韧效果以及复合材料的结晶度,但略微降低了PLA的拉伸强度。当PCL和滑石粉质量分数均为10%且加入0.5份的TBC后,PLA/PCL/滑石粉复合材料的断裂伸长率、拉伸强度、结晶度分别为13.3%,61.6 MPa,43.0%,相比纯PLA分别提高了533%,2%,73.4%。     

无卤阻燃PF/EP/GF布复合材料的固化性能和阻燃性能

采用环氧树脂(EP)作固化剂,2,4,6-三(二甲胺基甲基)-苯酚(DMP30)作固化促进剂改善酚醛树脂(PF)的固化性能,以氢氧化铝和有机磷阻燃剂协同改性其阻燃性能,将其涂覆于玻璃纤维(GF)布上,压制成无卤阻燃PF/EP/GF布复合材料.用傅立叶变换红外光谱(FTIR)仪和差示扫描量热(DSC)仪对无卤阻燃PF/EP/GF布复合材料的固化反应机理、固化反应动力学进行了分析研究,并测试了该复合材料的阻燃性能.结果表明,无卤阻燃PF/EP/GF布复合材料的固化反应表观活化能Ea=75.7 kJ/mol、反应级数n=0.91,起始固化温度、固化峰顶温度、固化终止温度分别为108.6、133.2、152.9℃;当氢氧化铝质量分数为14%、DMP30质量分数为1%、有机磷阻燃剂质量分数为4.8%时,无卤阻燃PF/EP/GF布复合材料的固化性能、阻燃性能均达到较佳状态.     

Improvement of microstructures and properties of poly(lactic acid)/poly(ε‐caprolactone) blends compatibilized with polyoxymethylene

Incompatibility of poly(lactic acid)/poly(?‐caprolactone) (PLA/PCL) (80:20) and (70:30) blends were modified by incorporation of a small amount of polyoxymethylene (POM) (≤3 phr). Impact of POM on microstructures and tensile property of the blends were investigated. It is found that the introduction of POM into the PLA/PCL blends significantly improves their tensile property. With increasing POM loading from zero to 3 phr, elongation at break increases from 93.2% for the PLA/PCL (70:30) sample to 334.8% for the PLA/PCL/POM (70:30:3) sample. A size reduction in PCL domains and reinforcement in interfacial adhesion with increasing POM loading are confirmed by SEM observations. The compatibilization effect of POM on PLA/PCL blends can be attributed to hydrogen bonding between methylene groups of POM and carbonyl groups of PLA and PCL. In addition, nonisothermal and isothermal crystallization behaviors of PLA/PCL/POM (70:30:x) samples were investigated by using differential scanning calorimetry and wide angle X‐ray diffraction measurements. The results indicate that the crystallization dynamic of PLA matrix increases with POM loadings. It can be attributed to the fact that POM crystals have a nucleating effect on PLA. While crystallization temperature is 100 °C, crystallization half‐time can reduce from 9.4 to 2.0 min with increasing POM loading from zero to 3 phr. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46536.     

Properties and structures of polylactide filled with poly(ε-caprolactone)-coated calcium carbonate

The poly(ε-caprolactone) (PCL)-coated microsized calcium carbonate (CaCO₃) was prepared by high-speed hybrid mechanical coating. Polylactide (PLA) was melt-blended with neat and modified CaCO₃ particles. Phase morphology, microstructure, and thermal dynamic rheological and mechanical properties of the composites were investigated. Differential scanning calorimetry reveals that the addition of coated CaCO₃ remarkably makes the cold crystallization temperature decrease but has little influence on the final degree of crystallinity of PLA. Dynamic rheological tests indicate that complex viscosity and loss modulus of modified CaCO₃ system are lower than those of neat CaCO₃ system. Scanning electron microscopic results show that the coated CaCO₃ microparticles disperse more uniformly in the PLA matrix compared with neat particles. The smooth and round coated particles promote the dispersion of CaCO₃ particles in the PLA matrix, and PCL enhances the interfacial adhesion between CaCO₃ particles and the PLA matrix. From mechanical tests, it is found that toughness of the composites is greatly improved by the incorporation of PCL-coated CaCO₃ microparticles. It is glad to see that the elongation at break of the composite with 15 phr coated CaCO₃ is as high as 310%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of poly(ε-caprolactone) and titanium (IV) dioxide content on the UV and hydrolytic degradation of poly(lactic acid)/poly(ε-caprolactone) blends

The effect of accelerated weathering degradation on the properties of poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends and PLA/PCL/titanium (IV) dioxide (TiO₂) nanocomposites are presented in this paper. The results show that both polymers are susceptible to weathering degradation, but their degradation rates are different and are also influenced by the presence of TiO₂ in the samples. Visual, microscopic and atomic force microsocpy observations of the surface after accelerated weathering tests confirmed that degradation occurred faster in the PLA/PCL blends than in the PLA/PCL/TiO₂ nanocomposites. The X-ray diffraction results showed the degradation of PCL in the disappearance of its characteristic peaks over weathering time, and also confirmed that PLA lost its amorphous character and developed crystals from the shorter chains formed as a result of degradative chain scission. It was further observed that the presence of TiO₂ retarded the degradation of both PLA and PCL. These results were supported by the differential scanning calorimetry results. The thermogravimetric analysis results confirmed that that PLA and PCL respectively influenced each other's thermal degradation, and that TiO₂ played a role in the thermal degradation of both PLA and PCL. The tensile properties of both PLA/PCL and PLA/PCL/TiO₂ were significantly reduced through weathering exposure and the incorporation of TiO₂.     

Interface,thermal, and Fourier transform—infrared spectroscopy investigation on polylactic acid/polyhydroxyalkanoate composites with silane-treated aluminum particles and intercalated montmorillonite inclusions for semiconductor devices

In this investigation, the dielectric properties of silane-influenced aluminum conductive particles in polylactic acid, polyhydroxyalkanoates, and intercalated montmorillonite (MMT) composite were assessed for enhancing the dielectric constant, dielectric loss, and AC conductivities. Eight different sets of samples were fabricated with untreated and silane-treated batches of biopolymer composites where the highest recorded dielectric constant was 3.98 at relaxation frequency of 10 kHz. One of the notable observations in the dielectric loss was with PLA/PHA/iMMT/Al (10 wt%) (silane-treated) composites exhibited the lowest losses past relaxation frequencies. Furthermore, FT-IR spectra were conducted on the samples to identify stretching and bonds created by silane and aluminum particles. The IR spectra confirm the formation of the Si O Al bond when treated with 3-glycidyloxypropyl-trimethoxysilane (GPTMS) solution and confirm the bond of Al OH hydroxyl bonds in the untreated composite samples. Other IR spectra information that was gathered would include carbonyl group stretching at 1750 cm⁻¹ and absorption bands of hydroxy acids, between 3511 and 3640 cm⁻¹, respectively. Scanning electron microscopy was performed on the sample to observe the formation of matrix cracks and exfoliation. A rough surface can be seen on PLA/PHA blends and the crystallization of these polymer blends regions can be vividly seen from the micrographs. Lastly, thermogravimetry analysis on the composite samples shows a predominant mass loss at 300°C before complete degradation and the notable composite with the lowest mass loss would be PLA/PHA/iMMT/Al (10 wt%) (ST) composite samples and with the inclusion of a constant 5 wt% organoclay MMT fillers imposed a high-onset degradation temperature, which was remarkable for composites that were fabricated through standard hot-press compression molding and cooling procedures.     

Toward environment‐friendly composites of poly(ε‐caprolactone) reinforced with stereocomplex‐type poly(l‐lactide)/poly(d‐lactide)

In this work, stereocomplex‐poly(l ‐ and d ‐lactide) (sc‐PLA) was incorporated into poly(ε‐caprolactone) (PCL) to fabricate a novel biodegradable polymer composite. PCL/sc‐PLA composites were prepared by solution casting at sc‐PLA loadings of 5–30 wt %. Differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD) demonstrated the formation of the stereocomplex in the blends. DSC and WAXD curves also indicated that the addition of sc‐PLA did not alter the crystal structure of PCL. Rheology and mechanical properties of neat PCL and the PCL/sc‐PLA composites were investigated in detail. Rheological measurements indicated that the composites exhibited evident solid‐like response in the low frequency region as the sc‐PLA loadings reached up to 20 wt %. Moreover, the long‐range motion of PCL chains was highly restrained. Dynamic mechanical analysis showed that the storage modulus (E′) of PCL in the composites was improved and the glass transition temperature values were hardly changed after the addition of sc‐PLA. Tensile tests showed that the Young's modulus, and yield strength of the composites were enhanced by the addition of sc‐PLA while the tensile strength and elongation at break were reduced. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40208.     

聚氨酯弹性体/Al(OH)_3复合材料工艺、性能及结构研究

以高活性聚醚三元醇、液化MDI、乙二醇等为主要原料,微米级Al(OH)3为填料,二月桂酸二丁基锡、三乙烯二胺为催化剂,采用一步法制备聚氨酯弹性体/Al(OH)3复合材料,考查了Al(OH)3含量对复合材料成型工艺、性能及微观结构的影响。结果表明:Al(OH)3对聚合反应有延迟作用并可作为聚氨酯弹性体的增强填料;氧指数表明,复合材料的阻燃性能随Al(OH)3含量的增加而提高,可达到难燃级别。XRD图和SEM照片表明微米级Al(OH)3在PUE基体中分散良好。     

PTCR characteristics of polycarbonate/nickel‐coated graphite‐based conducting polymeric composites in presence of poly(caprolactone)

The effect of poly(caprolactone) (PCL) on the positive temperature coefficient of resistivity characteristics of polycarbonate (PC)/nickel (Ni)‐coated graphite (40 wt%) composites was investigated. The PTC trip temperature of PC/Ni‐coated graphite composites appeared at 155°C. On addition of PCL to PC/Ni‐coated graphite composites, the PTC trip temperature reduced to 125°C, well below the T_g of the PC (∼147°C), as well as the PC/PCL (∼136°C) blend. It is noteworthy that the observed PTC effect for PC/PCL (8 wt%)/Ni‐coated graphite (40 wt%) composites is highly reproducible during many heating cycles. The coefficient of thermal expansion (CTE) of PC was increased in presence of PCL. Thus, the mismatch in CTE of the PC and Ni‐coated graphite at a temperature well below the T_g of PC was enough to disrupt the continuous network structure that increased the resistivity of the composites. Storage modulus of PC/PCL/Ni‐coated graphite composites was higher than PC/Ni‐coated graphite composites. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers