微波合成酚醛／蒙脱石纳米复合材料性能研究

对微波合成的酚醛树脂/蒙脱石纳米复合材料性能进行了测试,结果表明,复合材料性能得到大幅度提高.蒙脱石加入量为2%时,复合材料的流动性能最好,因为此时蒙脱石以剥离结构存在;若加入量继续增加,流动性开始下降.蒙脱石的加入大幅度提高了复合材料的拉伸强度、拉伸模量和断裂伸长率等力学性能.当蒙脱石加入量过多使其主要以聚集态存在时,反而会降低复合材料的力学性能.复合材料的热稳定性也得到了显著改善,分解温度和炭残留都有不同程度的提高,因蒙脱石在高温状态下可保护树脂.     

蒙脱石/TiO2复合材料制备及其光催化性能研究

以蒙脱土和钛酸丁酯为原料,采用溶胶凝胶法制备出蒙脱石/TiO2复合材料,利用XRD、SEM、光催化亚甲基蓝溶液对其物相组成、晶体结构、微观结构和光催化性能进行了研究.结果表明:TiO2以锐钛矿相分布于蒙脱石的层间域和表面,并使蒙脱石d001有不同程度的增大.蒙脱石/TiO2复合材料的加入量和Ti/蒙脱石比值、亚甲基蓝溶液的初始质量浓度对蒙脱石/TiO2复合材料的吸附和光催化效率均有影响.     

交联对聚乳酸/淀粉/纳米二氧化硅复合材料力学性能的影响

采用熔融共混方法制备聚乳酸/淀粉/纳米二氧化硅复合材料,研究了交联对聚乳酸/淀粉/纳米二氧化硅复合材料力学性能的影响,并且采用扫描电子显微镜(SEM)对复合材料的微观形貌进行分析,结果表明:交联能提升淀粉/聚乳酸的界面相容性,并能提高其力学性能,聚乳酸/淀粉/纳米二氧化硅的重量比例为70/20/10时,引发剂及交联剂添加量分别为0.1 phr及0.3 phr时,复合材料的拉伸强度及断裂伸长率分别提高为21.49 MPa及216.74%。     

聚乳酸/有机蒙脱土纳米复合材料的制备及降解性能研究

以聚乳酸和有机蒙脱土为原料,通过溶液插层法制备了聚乳酸/有机蒙脱土复合材料,分别用傅立叶变换红外光谱、X.射线衍射、热重分析等对聚乳酸/有机蒙脱土纳米复合材料的结构及热稳定性进行了表征,研究了材料的降解性能.结果表明,在聚乳酸/有机蒙脱土纳米复合材料中蒙脱土层间距为2.21 nm.层间距明显增大,表明聚乳酸分子插入到蒙脱土片层间,形成了插层型纳米复合材料.复合材料的热分解温度提高,热稳定性比纯PLA有明显的提高.在NaOH介质中降解结果表明,材料在碱性介质中降解性能和吸水性能良好.     

聚乙烯醇/蒙脱石纳米复合材料的制备与表征

以钠质蒙脱石和聚乙烯醇为原料,通过溶液插层-流延成膜法制备不同蒙脱石质量分数的聚乙烯醇/蒙脱石纳米复合材料薄膜。用X射线衍射(XRD)、扫描电子显微镜(SEM )和热重分析(TGA)对复合材料的结构进行了表征。结果表明,聚乙烯醇分子成功进入蒙脱石的层间,实现了在纳米尺度上的复合;蒙脱石质量分数高于7 5%形成插层型的纳米复合材料,低于7 .5%的形成剥离型的纳米复合材料;纳米复合材料的热稳定性比纯聚乙烯醇有较大提高。     

ATH和APP对聚乳酸/竹粉复合材料阻燃抑烟性能的影响

利用竹粉和聚乳酸为原料复合制备聚乳酸/竹粉复合材料,分别采用氢氧化铝(ATH)和聚磷酸铵(APP)阻燃剂对聚乳酸/竹粉复合材料进行阻燃抑烟处理并对阻燃处理后的复合材料进行性能测试。结果表明,两种阻燃剂的加入均使复合材料高温下的成炭率提高了约2倍,分别达到了24.7%和25.6%;ATH和APP的加入均有效提高了聚乳酸/竹粉复合材料的阻燃性能;其中,APP对复合材料燃烧过程中热量释放的抑制明显,其热释放速率在燃烧100s以后下降了近2倍,约为150kW/m2,但生烟量大;而ATH对复合材料的抑热效果不及APP,但抑烟效果显著,平均烟释放速率只有约0.02m2/s。     

聚乳酸/天然纤维复合材料阻燃性能研究进展

介绍了聚乳酸的合成方法和几类常见的天然纤维的成分结构等特性,综述了聚乳酸/天然纤维复合材料常见的制备方法。重点论述了聚乳酸/麻纤维复合材料、聚乳酸/椰壳纤维复合材料以及聚乳酸/竹纤维复合材料的制备过程以及阻燃性能的研究。论述了纤维的处理,阻燃剂的添加以及制备工艺对复合材料阻燃性能的影响,揭示了各种复合材料的阻燃机理,进而总结了影响阻燃性能的重要因素和调节方法。提供了提高天然可降解纤维复合材料的阻燃性能的有效方法并总结了现阶段研究的不足,对未来的研究方向进行了展望。     

马来酸酐接枝共聚物增容聚乳酸/改性淀粉复合材料的制备与性能研究

采用熔融共混方法制备聚乳酸/改性淀粉复合材料。研究了不同含量的马来酸酐接枝共聚物对聚乳酸/改性淀粉复合材料力学性能的影响,并且采用差示扫描量热(DSC)仪和扫描电子显微镜(SEM)对复合材料的微观结构进行分析。结果表明,马来酸酐接枝共聚物的加入改善了聚乳酸与淀粉的相容性,提高了复合材料的力学性能,添加量为0.5份时复合材料的拉伸强度提高了61.6%,断裂伸长率提高了53.1%,弯曲强度提高了104.7%,同时还能提高复合材料的热变形温度和耐水性;改性淀粉与聚乳酸两相紧密连接。     

聚合物/蒙脱石纳米复合材料研究进展

综述了蒙脱石的结构以及聚合物/蒙脱石纳米复合材料的制备原理与方法,重点介绍了纳米复合材料的制备方法与应用前景.     

反应挤出聚酰胺6/蒙脱石复合材料的中试

在小试研究的基础上进行反应挤出聚酰胺6/蒙脱石复合材料中试研究,重点考察脱水工艺条件对聚合的影响,螺杆转速对复合材料力学性能的影响,蒙脱石含量对复合材料力学性能的影响.中试结果显示:双螺杆挤出机各段的温度在140℃左右,随着螺杆转速的提高,复合材料的断裂伸长率、缺口冲击强度出现下降,拉伸强度、弯曲强度和弯曲模量增大,中试螺杆转速在110 r/min;随着蒙脱石含量的增加,复合材料的拉伸强度、弯曲模量呈升高趋势,而缺口冲击强度呈下降趋势,最佳蒙脱石含量为3%～4%;小试与中试的脱水工艺条件基本相当,中试产品颜色和力学性能好于小试产品.     

聚乳酸/纳米蒙脱土纳米复合材料的制备与挤出发泡研究

采用熔融插层法制备了聚乳酸/有机改性纳米蒙脱土（PLA/OMMT）复合材料,对其复合结构、力学性能、热性能、动态流变性能进行了测试和表征,并研究了复合材料的挤出发泡行为。结果表明,不同含量的OMMT与PLA进行熔融插层会形成不同的插层与剥离结构;3 %的OMMT可以提高PLA的力学性能、改善热性能;OMMT能够提升PLA的熔体强度,同时在挤出发泡过程中起到成核剂的作用,并且能够减弱发泡剂气体向PLA熔体外部的扩散,从而提高PLA挤出发泡的效果。     

Synergistic effects of polyethylene glycol and organic montmorillonite on the plasticization and enhancement of poly(lactic acid)

Poly(lactic acid) (PLA)/polyethylene glycol (PEG)/organic montmorillonite (OMMT) composites were prepared by melt blending, and their mechanical, rheological behavior, crystalline behavior, and thermal stability were investigated. Results showed that the elongation-at-break and notch-impact strength of PLA/15PEG/1.5OMMT were 466.45% and 4.34 kJ m⁻², respectively, which were nearly 42 and 2 times higher than those of PLA, respectively. The elongation-at-break of PLA/15PEG/1.5OMMT was also 33 times higher than that of PLA/15PEG and 30 times that of PLA/1.5OMMT. With addition of PEG, PLA chains could insert to OMMT effectively and increase the layer space of OMMT. The characteristics of dynamic behavior and fracture morphology showed that the plasticizer PEG could soften the PLA matrix, leading to easy plastic deformation. OMMT was well distributed in the PLA matrix and able to transfer the stress of external forces, thereby contributing to the matrix yielding initiation and expansion of polymer composites. The synergistic effect of OMMT and PEG was determined by studying the mechanical properties of PLA/PEG/OMMT composite. Differential scanning calorimetry and thermogravimetry studies revealed that OMMT as a nucleating agent improved crystallization and thermal stability. Thus, the synergistic effect of OMMT and PEG balanced the stiffness and toughness of PLA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47576.     

Physical,mechanical, and thermal properties of micronized organo‐montmorillonite suspension modified wood flour/poly(lactic acid) composites

In this study, micronized organo‐montmorillonite (OMMT) suspension was prepared with sodium‐montmorillonite (Na‐MMT), didecyl dimethyl ammonium chloride, and dispersant polyethylene glycol 1000 by a ball‐milling process. Then, wood flours (WFs) were impregnated with prepared OMMT suspension at a concentration of 0.5, 1.0, 2.0, or 4.0%. WFs were characterized by X‐ray diffraction and scanning electron microscopy. The hygroscopicity of WF was investigated by a vapor adsorption method. WFs were, respectively, blended with poly (lactic acid) (PLA) to produce WF/PLA composites. Thereafter, physical, mechanical, and thermal properties of the composites were tested. The results showed that a great amount of OMMT attached on the surface of WF, partly penetrating into the microstructure of WF. Owing to the hydrophobicity of OMMT, the vapor adsorption of OMMT‐modified WF decreased. The composite which was produced by WF treated with 0.5% OMMT suspension, showing an increment in the physical, mechanical, and thermal properties. However, OMMT should not be overloaded. Otherwise, the accumulation of OMMT might cause poor interfacial adhesion between WF and PLA matrix. POLYM. COMPOS., 36:731–738, 2015. © 2014 Society of Plastics Engineers     

聚乳酸/有机蒙脱土纳米插层复合材料的原位插层聚合工艺及结构表征研究

采用新疆夏子街钠基蒙脱土为原矿制备的有机蒙脱土和丙交酯,通过原位插层聚合方法,合成聚乳酸/有机蒙脱土纳米复合材料.通过对反应体系真空度、催化剂用量、反应温度、反应时间和OMMT 加入量等对工艺条件的研究,确定了最佳合成条件.结果为:反应体系真空度为0.085 MPa,催化剂用量为丙交酯质量的0.5%,聚合反应的温度控制在170 ℃,聚合反应时间7 h,OMMT加入量3%(质量含量).采用傅立叶红外光谱仪、X射线衍射仪、扫描电子显微镜、透射电子显微镜对聚乳酸/有机蒙脱土纳米插层复合材料的微观结构、相态等进行了表征和分析.     

Preparation,characterization, and biodegradation of PS:PLA and PS:PLA:OMMT nanocomposites using Aspergillus niger

Poly(lactic acid) (PLA) was synthesized using l ‐lactic acid by condensation polymerization. Polystyrene (PS) and surface modified montmorillonite (OMMT) was used for the preparation of PS:PLA composites and PS:PLA:OMMT nanocomposites. The composite materials prepared had varying amount of PLA (10–30%) and OMMT (0.5–5 phr). These composites were subjected to degradation in minimal medium using the fungi Aspergillus niger (A. niger) under controlled conditions. Scanning electron microscopy (SEM) showed the growth of microorganism on the polymer surface and fracture within the polymer matrix as a result of degradation. Fourier transform infra red spectroscopy (FTIR) was further used to determine the mechanism leading to biodegradation. It was found that the biodegradation of both PS:PLA and PS:PLA:OMMT took place mainly via break down and utilization of ester group, as can be seen from disappearance of absorption peak of ester group and simultaneous appearance of a typical IR absorption of microbial mass at 1450 cm⁻¹. The thermal stability of PS:PLA:OMMT nanocomposites was found to increase with increasing concentration of OMMT, as observed from thermo gravimetric analysis (TGA), while mechanical property was found to be decreased after degradation at 30% of PLA and 5 wt% of OMMT content. Change in extracellular protein content, biomass production and % degradation with respect to time (up to 28 days) were studied and correlated to evaluate the effectiveness of A. niger in biodegradation of the composites. POLYM. COMPOS., 35:263–272, 2014. © 2013 Society of Plastics Engineers     

PLA/OMMT纳米插层复合材料的合成、表征及降解性研究

以乳酸单体和有机蒙脱土(OMMT)为原料,通过原位插层聚合法合成了聚乳酸(PLA)/OMMT纳米插层复合材料, 分别采用傅立叶变换红外光谱( FT-IR)、X 射线衍射（XRD）、透射电子显微镜（TEM）等对PLA/OMMT复合材料的结构、形貌进行了表征和分析,同时研究了材料的降解性能。FT-IR表明,OMMT在聚合过程中被剥离成很小的粒子并分散在PLA基体中形成PLA/OMMT复合材料。由XRD分析可知MMT的层间距为1.260 nm,OMMT层间距为1.993 nm,PLA/OMMT复合材料中OMMT层间距为2.287 nm,层间距明显增大,表明PLA分子链插入到OMMT片层间,实现了原位插层聚合。透射电镜（TEM）分析表明,制备的PLA/OMMT复合材料形成了插层型结构,与红外光谱与XRD表征结果吻合。降解试验表明,介质对材料降解作用的次序为：NaOH＞HCl＞去离子水。在磷酸盐缓冲溶液中,随着降解时间的延长,材料的特性黏度在降解过程中不断下降。PLA/OMMT复合材料的降解速度要快于PLA,表明由于OMMT纳米粒子的存在,会加速材料的降解。     

Effect of organically modified montmorillonite (OMMT) on biodegradation of PS:PLA and PS:PLA:OMMT using Phanerochaete chrysosporium

The environmental issues of synthetic polymers have been resolved using biodegradation under controlled conditions. The degradation study of polymeric composites of (a) polystyrene (PS) and poly(lactic acid) (PLA) (PS:PLA), and (b) PS:PLA filled with organically modified montmorillonite (OMMT) (PS:PLA:OMMT) was carried out using Phanerochaete chrysosporium . PLA was synthesized using l ‐lactic acid under controlled ultrasound cavitation technique, dried and added to a solution of PS. Surface of montmorillonite (MMT) was modified using column chromatographic technique to improve d‐spacing up to 31.5 Å. The sheets of PS:PLA and PS:PLA:OMMT were subjected to degradation study in minimal medium using P. chrysosporium micro‐organism under controlled conditions up to 28 days. The growth of micro‐organism and fractures inside the polymer matrix before and after degradation was observed using scanning electron microscope. Change in extracellular protein content, biomass production, and % degradation with respect to time of incubated samples have been also studied. It was found that the PS:PLA:OMMT (at 5 phr OMMT content) and PS:PLA (at 30% PLA) composites show an increment in degradation. The presence of OMMT leads to faster degradation of PS:PLA:OMMT nanocomposites, which decreases in mechanical property by 30% of PLA and 5 wt% of OMMT content. POLYM. COMPOS., 38:1292–1301, 2017. © 2015 Society of Plastics Engineers     

熔融插层法制备聚乳酸/有机蒙脱土纳米复合材料及其性能研究

以新疆地产蒙脱土和聚乳酸为原料,通过熔融插层的方法制备了聚乳酸(PLA)/有机蒙脱土（OMMT）纳米复合材料。分别采用X射线衍射仪、扫描电子显微镜、透射电子显微镜、热重分析仪等对复合材料的微观结构、形貌及热稳定性进行了表征和分析。研究表明,PLA大分子链已经插入OMMT片层间,层间距明显增大,形成PLA/OMMT纳米复合材料,体系的相容性良好。PLA/OMMT纳米复合材料的热失重曲线移向高温端,其热分解温度提高。PLA/OMMT纳米复合材料的熔点、维卡软化点、冲击强度、拉伸强度、热稳定性均比PLA基体有明显的提高。PLA/OMMT纳米复合材料的降解性初步研究表明其是一种良好的生物可降解环保塑料。     

Studies on morphologies and thermal properties of poly(lactic acid)/polycaprolactone/organic‐modified montmorillonite nanocomposites

Poly(lactic acid)/organic montmorillonite (PLA/OMMT) nanocomposites were prepared via twin‐screw extrusion. Montmorillonite (MMT) was firstly organically modified to improve the compatibility between polyester and MMT. The effects of ratio between PLA and OMMT and the addition of polycaprolactone (PCL), as a compatilizer, on the properties of PLA/OMMT nanocomposites were studied. The morphology and the properties of the nanocomposites were characterized by XRD, DSC, and TEM. Using OMMT, the intercalated structure was formed during the extrusion process and the OMMT interlayers space was enlarged. More OMMT content was apt to form thicker structure with more stacked individual silicate layers, which led to lower degree of crystallinity of PLA. It showed that 1 phr OMMT could result in the largest interlayers space and the best crystallization state. PCL can effectively increase the binding force between two phases and improve the order of the nanocomposites. In addition, the annealing after treatment can form regular structure and enhance the thermal properties of nanocomposites. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Mechanical,thermal, and morphological properties of injection molded poly(lactic acid)/SEBS‐g‐MAH/organo‐montmorillonite nanocomposites

Poly(lactic acid)/organo‐montmorillonite (PLA/OMMT) nanocomposites toughened with maleated styrene‐ethylene/butylene‐styrene (SEBS‐g‐MAH) were prepared by melt‐compounding using co‐rotating twin‐screw extruder followed by injection molding. The dispersibility and intercalation/exfoliation of OMMT in PLA was characterized using X‐ray diffraction and transmission electron microscopy (TEM). The mechanical properties of the PLA nanocomposites was investigated by tensile and Izod impact tests. Thermogravimetric analyzer and differential scanning calorimeter were used to study the thermal behaviors of the nanocomposite. The homogenous dispersion of the OMMT silicate layers and SEBS‐g‐MAH encapsulated OMMT layered silicate can be observed from TEM. Impact strength and elongation at break of the PLA nanocomposites was enhanced significantly by the addition of SEBS‐g‐MAH. Thermal stability of the PLA/OMMT nanocomposites was improved in the presence of SEBS‐g‐MAH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012