表面处理对可生物降解黄麻/PLA复合材料结构和性能的影响

采用注塑成型法制备了生物降解黄麻短纤维增强PLA复合材料,通过力学性能测试及SEM,探讨了碱处理、碱和硅烷偶联剂KH550同时处理对复合材料结构和性能的影响。结果表明:两种处理方法均能够增加黄麻纤维的表面粗糙度,但碱和偶联剂KH550同时处理的效果要优于碱处理,且KH550改善了黄麻短纤维与PLA树脂之间的界面黏结性能提,高了黄麻/PLA复合材料的拉伸强度和弯曲强度。     

界面调控对聚乳酸/竹纤维复合材料热性能及动态热力学性能的影响

分别采用碱(NaOH)处理、异氰酸酯(MDI)处理以及NaOH+MDI处理3种方法对竹纤维(BF)和聚乳酸(PLA)的界面进行调控,并通过注射成型工艺制备了PLA/BF复合材料,探讨了不同界面调控方法对PLA/BF复合材料热性能与动态热力学性能的影响。结果表明,3种界面调控处理均可以改善PLA/BF复合材料的热稳定性和动态热力学性能;NaOH和MDI联合调控可以产生协同效应,对PLA/BF复合材料热稳定性和动态热力学性能的改善效果更显著。     

汽车内饰用PP/黄麻纤维复合材料力学性能

采用转矩流变仪混合造粒,通过注射成型方法制备了聚丙烯(PP)/黄麻纤维复合材料,研究了对纤维表面进行处理的NaOH浓度、纤维含量和相容剂的含量对PP/黄麻纤维复合材料力学性能的影响,采用扫描电镜对纤维表面及复合材料的断面形貌进行分析。结果表明:黄麻纤维经过碱处理后PP/黄麻纤维复合材料的力学性能优于纤维未处理的复合材料的力学性能,随着NaOH浓度的提高,PP/黄麻纤维复合材料的拉伸强度和冲击强度增加,在NaOH浓度为16%时,其拉伸强度和冲击强度最佳;其弯曲强度随着NaOH浓度的提高先增加而后下降,在8%浓度时,弯曲强度最大。随着纤维含量的提高,PP/黄麻纤维复合材料的拉伸强度和弯曲强度先增加后下降,在纤维含量达到20%时,PP/黄麻纤维合材料的拉伸强度和弯曲强度达到最大。随着纤维含量的提高,PP/黄麻纤维复合材料的冲击强度降低。相容剂的加入使得PP/黄麻纤维复合材料的拉伸强度和弯曲强度明显增加。     

腰果酚接枝黄麻纤维不饱和聚酯复合材料的力学性能及界面调控

用甲苯二异氰酸酯与腰果酚(CNSL)合成大分子偶联剂接枝黄麻纤维。以接枝的黄麻纤维为增强体,通用的不饱和聚酯树脂为基体,采用热压方式制备复合材料。比较了纯饱和聚酯树脂、5 %CNSL增韧的不饱和聚酯树脂、25 %碱处理的黄麻纤维不饱和聚酯树脂复合材料和25 %的CNSL接枝黄麻纤维不饱和聚酯树脂复合材料的拉伸强度和冲击强度。结果表明,CNSL接枝于黄麻纤维上;CNSL的加入能提高材料的韧性,黄麻纤维能提高材料的拉伸强度而不能提高材料韧性;25 %CNSL接枝的黄麻纤维不饱和聚酯树脂能提高材料的拉伸强度和韧性,25 %CNSL接枝的黄麻纤维增强含5 %CNSL的不饱和聚酯复合材料,其冲击强度为12.10 kJ/m^2。     

MCC对PLA/PPC复合材料力学性能与热稳定性的影响

以微晶纤维素(MCC)作为改性剂,马来酸酐接枝聚乳酸(PLA g MAH)为界面相容剂,聚乳酸(PLA)、聚碳酸亚丙酯(PPC)为基体,通过熔融共混法制得PLA/PPC/MCC三元复合材料。采用控温拉伸、动态热分析、扫描电子显微镜以及热失重分析等方法研究了MCC对PLA/PPC的力学性能和热稳定性。结果表明,PLA/PPC/MCC三元复合材料的拉伸强度提高了12.7 %,玻璃化转变温度（Tg）提高了9.8 ℃;PLA g MAH的加入可以改善PLA/PPC/MCC三元复合材料的界面性质,从而提高力学性能和热稳定性;当PLA g MAH的添加量为5 %（质量分数,下同）时,三元复合材料在常温下的拉伸强度、弯曲强度和冲击强度分别提高了53.7 %、43.1 %和18.5 %;在60 ℃下三元复合材料的断裂强度提高了80 %;热降解温度以及最大失重温度与PLA/PPC相比分别提高了25.31 ℃和61.83 ℃。     

制备工艺对PLA/PBAT/OMMT三元复合材料微观结构与性能的影响

采用两步法工艺,先制备聚乳酸/有机改性蒙脱土（PLA/OMMT）复合材料,然后将其与聚己二酸/对苯二甲酸丁二醇酯（PBAT）共混制得（PLA/OMMT）/PBAT复合材料,再与一步法工艺制备的PLA/PBAT/OMMT复合材料进行性能对比研究。对复合材料中不同相的界面张力进行了测试,对复合材料的微观结构进行了透射电子显微镜和扫描电子显微镜观察,对PLA的熔融与结晶行为进行了分析。结果表明,OMMT的加入降低了PBAT分散相尺寸,模糊了PLA与PBAT之间的相界面,改善了二者间的相容性;两步法工艺制得的复合材料中OMMT对PLA和PBAT两相增容效果及分散相的均匀性均优于一步法;在亲和性的作用下OMMT倾向于分布在PLA相以及PLA与PBAT相界面处;OMMT与PBAT协同增韧PLA效果明显。     

剑麻纤维/聚乳酸复合材料的制备及性能研究

采用蒸馏水、Na OH溶液、干法接枝马来酸酐(MAH)、酰化接枝月桂酸(GML)四种方式处理剑麻纤维(SF),用压制成型法制备纤维/聚乳酸(PLA)复合材料。利用红外光谱表征处理后的剑麻纤维。通过力学性能测试和扫描电镜分析表明,复合材料随着纤维含量的增多、层数增加,冲击强度与拉伸强度明显提高。加入70%的同向交错四层纤维时,SF/PLA复合材料的拉伸强度提高到104.5 MPa、冲击强度提高到135.86 J/m。纤维表面处理可以明显改善复合材料的界面相容性。     

溶液法制备PLA/改性长石复合材料及其性能表征

以KH570为改性剂对哈密长石进行湿法表面改性。以改性长石作为填料,通过溶液法制备了PLA/改性长石复合材料,对其性能及微观结构进行了测试和表征。界面接触角测试表明,经改性后界面接触角明显增大,表面有机憎水,具有亲油性,与FT-IR分析结果相吻合;力学性能测试表明,5%改性长石的加入有助于改善PLA复合材料的拉伸强度;TGA分析表明PLA/改性长石复合材料的热分解温度比PLA基体提高了4.47℃,表明其热稳定性得以提高;DSC分析表明,改性长石可以消除PLA复合材料的冷结晶,有助于提高PLA复合材料的结晶度,与XRD分析相吻合。测试结果表明,改性长石在PLA基质中起到了异相成核的作用,促进了PLA基质的结晶。     

硅烷偶联剂对PLA/木粉复合材料性能的影响

以30%木粉和70%聚乳酸(PLA)为原料,加入1%的硅烷偶联剂,通过熔融共混的方法制备了PLA/木粉复合材料,并研究了不同类型硅烷偶联剂对PLA/木粉复合材料结晶性能、热性能、力学性能和吸水率的影响。XRD结果表明:偶联剂KH-550明显降低了复合材料的结晶度,提高了木粉与PLA之间的相容性;热分析结果表明,偶联剂的加入使复合材料的冷结晶温度下降,热稳定性也稍有下降;力学性能测试结果表明:偶联剂的加入改善了复合材料的力学强度,且KH-550的改性效果较好;另外,KH-550的加入还增加了复合材料的耐水性。     

PLA/淀粉增容增塑的研究进展

聚乳酸(PLA)/淀粉复合材料是一种新型的绿色材料,生物降解性能优良,但是聚乳酸(PLA)/淀粉复合材料的力学性能较差,文章通过在共混体系中引入小分子增塑剂或大分子增塑剂以及通过发生酯化反应,使其分别具有外增塑和内增塑PLA/淀粉复合材料的作用,一步法反应增容不仅降低了淀粉结晶度,而且在界面处形成"架桥";两步法接枝形成与淀粉或PLA具有相同结构的共聚物PLA/淀粉复合材料,改善了复合材料的相容性。增容增塑聚乳酸(PLA)/淀粉复合材料能够提高复合材料的界面作用强度,降低PLA的脆性,改善淀粉的流动性能,极大地提高了复合材料的力学强度,并进一步总结了增容增塑改善PLA/淀粉复合材料界面作用的机理。     

Preparation and properties of successive alkali treated completely biodegradable short jute fiber reinforced PLA composites

The natural fiber reinforced biodegradable polymer composites were prepared with short jute fiber as reinforcement in PLA (Poly lactic acid) matrix. The short jute fiber is successively treated with NaOH at various concentrations (5%, 10%, and 15%) and H₂O₂. The composites were prepared with untreated and treated short jute fibers at different weight proportions (up to 25%) in PLA and investigated for mechanical properties. The results showed that the composite with successive alkali treated jute fiber at 10% NaOH and H₂O₂ with 20% fiber loading has shown 18% higher flexural strength than neat PLA and untreated jute/PLA composite. The flexural modulus of the composite at 25% fiber loading was 125% and 110% higher than that of composites with untreated fibers and neat PLA, respectively. The impact strength of composite with untreated fibers at higher fiber weight fraction was 23% high as compared to neat PLA and 26% high compared to composite with treated fibers. The water absorption was more for untreated jute/PLA composite at 25% fiber loading than all other composites. The composite with untreated fibers has high thermal degradation compared with treated fibers but lower than that of pure PLA matrix. The enzymatic environment has increased the rate of degradation of composites as compared to soil burial. Surface morphology of biodegraded surfaces of the composites were studied using SEM method. POLYM. COMPOS., 37:2160–2170, 2016. © 2015 Society of Plastics Engineers     

A Comparative Study on the Mechanical Properties of Jute and Sisal Fiber Reinforced Polymer Composites

The aim of the present study is to investigate and compare the mechanical properties of raw jute and sisal fiber reinforced epoxy composites with sodium hydroxide treated jute and sisal fiber reinforced epoxy composites. This is followed by comparisons of the sodium hydroxide treated jute and sisal fiber reinforced composites. The jute and sisal fibers were treated with 20% sodium hydroxide for 2 h and then incorporated into the epoxy matrix by a molding technique to form the composites. Similar techniques have been adopted for the fabrication of raw jute and sisal fiber reinforced epoxy composites. The raw jute and sisal fiber reinforced epoxy composites and the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites were characterized by FTIR. The mechanical properties (tensile and flexural strength), water absorption and morphological changes were investigated for the composite samples. It was found that the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites exhibited better mechanical properties than the raw jute and raw sisal fiber reinforced composites. When comparing the sodium hydroxide treated jute and sisal fiber reinforced epoxy composites, the sodium hydroxide treated jute fiber reinforced composites exhibited better mechanical properties than the latter.     

黄麻纤维增强聚丙烯的力学性能

本文讨论了注塑成型黄麻纤维增强聚丙烯的制备方法和力学性能.将纤维重量含量分别为10%、20%和30%的复合材料进行比较,分析纤维含量对复合材料拉伸、弯曲和冲击性能的影响;将纤维分别切成约3mm、5mm和10mm长制成复合材料进行比较,分析纤维长度对复合材料拉伸、弯曲和冲击性能的影响.掺入黄麻纤维能使聚丙烯的拉伸和弯曲性能提高,但使其冲击强度降低;随纤维含量的增加或纤维长度的增加,复合材料的强度和模量是递增的,而冲击强度是递减的.     

Development of Silicon Carbide Reinforced Jute Epoxy Composites: Physical,Mechanical and Thermo-mechanical Characterizations

The aim of the present study was to investigate the physical and thermo-mechanical characterization of silicon carbide filled needle punch nonwoven jute fiber reinforced epoxy composites. The composite materials were prepared by mixing different weight percentages (0–15 wt.%) of silicon carbide in needle punch nonwoven jute fiber reinforced epoxy composites by hand-lay-up techniques. The physical and mechanical tests have been performed to find the void content, water absorption, hardness, tensile strength, impact strength, fracture toughness and thermo-mechanical properties of the silicon carbide filled jute epoxy composites. The results indicated that increase in silicon carbide filler from 0 to 15 wt.% in the jute epoxy composites increased the void content by 1.49 %, water absorption by 1.83 %, hardness by 39.47 %, tensile strength by 52.5 %, flexural strength by 48.5 %, and impact strength by 14.5 % but on the other hand, decreased the thermal conductivity by 11.62 %. The result also indicated that jute epoxy composites reinforced with 15 wt.% silicon carbide particulate filler presented the highest storage modulus and loss modulus as compared with the unfilled jute epoxy composite.     

Overmolded polylactide/jute-mat eco-composites: A new method to enhance the properties of natural fiber biodegradable composites

Environmentally friendly, biodegradable composites were prepared via overmolding of poly(lactic acid) (PLA) onto PLA/jute-mat, named as “ecosheets,” reinforced continuous fiber composite sheets. Film stacking procedure was used to prepare ecosheets via using a hot-press. The fiber orientation was changed as −45°/+45° and 0°/0°. −45°/+45° orientation exhibited higher properties as compared to 0°/0° for ecosheets; therefore, this construction was used to produce overmolded composites (OMCs). The mechanical tests showed that flexural modulus and strength of OMCs were improved in comparison to neat PLA. The dynamic mechanical analysis exhibited that the thermomechanical resistance of PLA was enhanced for OMCs. Scanning electron microscopy investigation showed that the jute/PLA interphase needs to be improved to further increase the properties. It was concluded that one of the biggest advantages of this novel technique was the increase of mechanical properties of PLA without altering the density. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48692.     

Mechanical and viscoelastic properties of soybean oil thermoset reinforced with jute fabrics and carded lyocell fiber

Composites and hybrid composites were manufactured from renewable materials based on jute fibers, regenerated cellulose fibers (Lyocell), and thermosetting polymer from soybean oil. Three different types of jute fabrics with biaxial weave architecture but different surface weights, and carded Lyocell fiber were used as reinforcements. Hybrid composites were also manufactured by combining the jute reinforcements with the Lyocell. The Lyocell composite was found to have better mechanical properties than other composites. It has tensile strength and modulus of about 144 MPa and 18 GPa, respectively. The jute composites also have relatively good mechanical properties, as their tensile strengths and moduli were found to be between 65 and 84 MPa, and between 14 and 19 GPa, respectively. The Lyocell‐reinforced composite showed the highest flexural strength and modulus, of about 217 MPa and 13 GPa, respectively. In all cases, the hybrid composites in this study showed improved mechanical properties but lower storage modulus. The Lyocell fiber gave the highest impact strength of about 35 kJ/m², which could be a result of its morphology. Dynamic mechanical analysis showed that the Lyocell reinforced composite has the best viscoelastic properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and mechanical characterization of chicken feather/PLA composites

Green composites, a bio‐based polymer matrix is reinforced by natural fibers, are special class of bio‐composites. Interest about green composites is continuously growing because they are environment‐friendly. This study describes the preparation and mechanical characterization of green composites using polylactic acid (PLA) matrix including chicken feather fiber (CFF) as reinforcement. Extrusion and an injection molding process were used to prepare CFF/PLA composites at a controlled temperature range. CFF/PLA composites with fiber mass content of 2%, 5%, and 10% were manufactured. The effects of fiber concentration and fiber length on mechanical properties of CFF/PLA composites have been studied. Mechanical properties of composites were investigated by tensile, compression, bending, hardness, and Izod impact testing. The results of experiments indicated that Young's modulus, compressive strength, flexural modulus, and hardness of the PLA reinforced CFF composites are higher but tensile strength, elongation at break, bending strength and impact strength of them are lower than pure PLA. The results indicate that these types of composites can be used for various applications. POLYM. COMPOS., 38:837–845, 2017. © 2015 Society of Plastics Engineers