煤矸石粉的改性及其对SBS力学性能的影响

为进一步改善超细煤矸石粉的表面活性,利用具有偶联和润滑作用的聚合助剂Wy1502对超细煤矸石粉进行表面改性,采用混炼工艺制备了SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)/超细煤矸石粉复合材料。通过傅立叶红外光谱(FTIR)、扫描电镜(SEM)、热重分析(TGA)、力学性能和熔体流动性测试等手段对粉体结构和复合体系的性能进行了分析。结果表明,助剂Wy1502与超细煤矸石粉间能形成化学结合,并有效阻止粉体颗粒的团聚;改性后超细粉体与SBS界面相容性改善,使材料力学性能明显提高,加工性降低,热稳定性提高。     

表面处理剂对PVC仿木复合材料性能的影响

使用4种不同类型的含高活性反应基团的聚氨酯处理剂对木粉表面进行处理,并制备了聚氯乙烯(PVC)/木粉复合材料,研究了表面处理剂的交联度、不同用量和高活性反应基团—NCO的含量对复合材料性能及结构的影响。结果表明,使用聚氨酯处理剂对木粉表面进行处理可以明显改善复合材料的流变性能,并明显提高复合材料的力学性能;扫描电镜观察表明,木粉经聚氨酯处理剂改性后与PVC的相容性明显得到改善。     

稀土偶联剂在再生PP/木粉复合材料中的应用研究

用稀土偶联剂(WOT)处理木粉,对改性木粉进行了红外光谱分析;将改性木粉、再生聚丙烯(PP)及其它助剂用双螺杆造粒机组挤出造粒制备PP/木粉复合材料,研究了WOT用量、木粉用量对复合材料性能的影响,并采用扫描电子显微镜进行了材料断面的形态分析。结果表明,WOT与木粉之间的化学结合作用可以增强木粉与PP的界面结合,提高了塑木复合材料的性能,合适的WOT用量为4～6份(每100份木粉)。木粉用量在20～60份时,复合材料的拉伸弹性模量、弯曲弹性模量和热变形温度随木粉用量的增加而提高。     

阴离子聚合PA6/木粉复合材料的制备及性能

利用二苯甲烷二异氰酸酯(MDI)、硅烷偶联剂(KH550)2种试剂对木粉表面接枝改性,在碱性催化剂条件下,将改性后的木粉与己内酰胺单体混合,使其发生阴离子聚合反应,制备聚酰胺6(PA6)/木粉复合材料,对其进行测试及表征,研究PA6/木粉复合材料的微观结构、力学性能和摩擦特征.研究结果表明,木粉表面成功接枝了MDI和K...     

竹粉的表面改性及其对聚丙烯基复合材料性能的影响

用偶联剂KH-550和硬脂酸对氢氧化钠溶液(10wt%)处理过的竹粉(BF)表面进行二次改性,然后通过熔融挤出制备了竹粉/聚丙烯(BF/PP)木塑复合材料.采用热重-差热分析(TG/DTA)、红外光谱(FTIR)、X射线衍射(XRD)和原子力显微镜(AFM)等对改性前后竹粉的微观结构进行表征.结果表明,改性后BF的热稳定性升高,比表面积增大,形成疏松的纤维聚集束;复合材料的力学性能显著提高;其中用KH-550改性竹粉制备的复合材料力学性能最佳,冲击强度较纯PP提高了83%.复合材料冲击断面扫描电镜(SEM)显示,KH-550改性可以明显提高BF与PP基体树脂间的相容性.     

不同表面改性对竹纤维/超高分子量聚乙烯复合材料摩擦学性能的影响

采用不同浓度氢氧化钠(Na OH)溶液对竹纤维(BF)的表面碱预处理,再使用硅烷偶联剂3-氨基丙基三乙氧基硅烷(KH550)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)三种不同表面改性后,与超高分子量聚乙烯(UHMWPE)粉料共混,通过模压成型工艺制备BF/UHMWPE复合材料。借助傅立叶变换红外光谱(FTIR)和热重分析(TG)研究改性前后BF的化学结构和热稳定性变化,使用摩擦磨损试验机测试三种不同表面改性BF增强UHMWPE复合材料的摩擦磨损性能,通过扫描电镜(SEM)观察改性前后BF的表面结构及复合材料的摩擦表面形貌并分析磨损机理。结果表明,10%NaOH和KH550协同改性能有效改善BF与UHMWPE的界面相容性,此时制备的复合材料干滑动摩擦因数为0. 11,磨损率较纯UHMWPE下降了46%,耐磨性显著提高,表现为轻微的疲劳磨损。     

木粉增强HDPE复合材料的制备及其性能研究

以废弃木粉为增强材料,采用双螺杆挤出机,制备木粉增强高密度聚乙烯复合材料,研究改善木粉增强高密度聚乙烯复合材料力学性能的途径。结果表明,随着木粉加入量的增加复合体系的力学性能得到明显改善;通过适当的方法对木粉进行表面处理、对基体树脂进行改性,可以有效地提高复合体系的界面粘接强度,大幅度改善复合体系的力学性能;采用短切玻璃纤维与木粉组合,可以获得力学性能很高,能作为结构材料使用的复合材料。     

木粉增强聚丙烯力学性能的改善方法

以废弃木粉为增强材料,制备了木粉增强聚丙烯复合材料,研究了改善废弃木粉增强聚丙烯复合材料力学性能的途径。结果表明,通过适当的处理方法对木粉进行表面处理、对基体树脂进行改性,可以有效地提高复合体系的界面粘接强度,能大幅度改善复合体系的力学性能;采用短切玻璃纤维及玻璃纤维毡与废弃木粉组合,可以获得力学性能很高、能作为结构材料使用的复合材料。     

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。     

木质素填充LDPE、EVA对复合物性能的影响

以木质素为填充剂分别与低密度聚乙烯(LDPE)、乙烯-乙酸乙烯酯共聚物(EVA)共混,经双螺杆造粒机共混挤出造粒,再经吹塑成膜。研究了木质素/LDPE、木质素/EVA共混物薄膜的表面形貌、力学性能、热性能和红外光谱。热分析表明木质素与EVA共混物的热稳定性比木质素与LDPE的共混物热稳定性好;红外光谱分析表明木质素与EVA分子间产生了强烈的相互作用,扫描电镜分析表明木质素与EVA共混的相容性较好,力学性能分析表明低于30%的木质素与LDPE、EVA共混力学性能较好。     

EV树脂基防水涂层的表面超疏水设计研究

本文选用常见的乙烯-醋酸乙烯酯共聚乳液（EVA）作为防水涂层的基料,对其表面进行疏水性设计,考察防水涂层的影响因素。将制备的 SiO₂颗粒进行有机改性,在 EVA表面负载改性的 SiO₂颗粒形成粗糙结构,接枝三甲氧基硅烷控制材料的润湿性能,达到对涂层表面的亲疏水性进行调控的目的。结果表明：制备的 SiO₂粒径 D97为 7 μm,红外光谱分析表明 SiO₂有机改性比较成功,SEM测试表明 SiO₂负载在 EVA表面,通过结构和化学亲疏水性设计的 EVA膜的接触角达到了 172. 9°。防水涂层在水中浸泡 72 h后,其水接触角仍维持在 170°左右,具有很好的疏水稳定性,表现出较好的应用潜力。     

木粉表面处理对PVC／木粉复合材料性能的影响

使用钛酸酯偶联剂、油酸酰胺、聚氨酯预聚物三种表面改性剂处理木粉并制备了PVC／木粉复合材料，研究了表面改性剂的不同种类和不同用量对复合体系性能和结构的影响。结果表明：几种木粉表面处理剂均可明显提高复合材料的力学性能，其中使用4份聚氨酯预聚体和6份油酸酰胺处理木粉表面的复合体系的力学性能较优；使用表面改性剂处理木粉，也可以明显改善复合体系的流变性能；同时扫描电镜观察也发现同样规律，体系中添加改性剂，PVC与木粉的相容性明显改善，材料性能也有所提高，但表面改性剂用量过多，也会造成木粉团聚，从而影响复合材料的性能。     

Effect of surfactant on EG dispersion in EVA and thermal and mechanical properties of the system

The influence of expanded graphite (EG) and sodium dodecyl sulfate (SDS) modified EG on the structure, thermal stability, and mechanical properties of ethylene vinyl acetate (EVA) was investigated in this study. The EVA filled with EG platelets, with and without anionic SDS modification, was prepared by melt mixing using a Brabender Plastograph mixer. The extent of dispersion and morphology of the composites were characterized using scanning electron microscopy (SEM), optical microscopy (OM), and X‐ray diffraction (XRD). The optical microscopy results show better distribution of the modified EG platelets in the EVA matrix, while the SEM results show an improved interfacial adhesion between the polymer and the SDS‐EG particles. Both the EVA18 copolymer and the EG platelets have monoclinic phases, and both EG and SDS do not seem to have any influence on the melting and crystallization behavior of the EVA18. The addition of EG enhanced the thermal stability of EVA18, and this stabilizing influence was further improved when the EG was treated with SDS. All the tensile properties of EVA/EG improved after surface modification. The storage modulus of EVA generally increased with increasing both the unmodified EG and the SDS modified EG content. There was a shift in the T_g to higher temperatures with an increase in both the EG and modified EG content. The α‐relaxation peak in the SDS modified EG curves was less intense than the β‐relaxation peak, even for the untreated EG composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41352.     

改性橡胶木粉/HDPE复合材料结构和力学性能的研究

用硅烷偶联剂A-171和天然橡胶胶乳(MGL-30)改性碱处理后的橡胶木粉。研究了木粉粒径、改性剂和木粉质量分数对橡胶木粉填充HDPE复合材料力学性能的影响,并对复合材料的断面形貌和木粉的表面结构进行了SEM分析。结果表明:木粉粒径、改性剂及木粉质量分数对复合材料力学性能有较大的影响。改性后木粉与基体HDPE的界面粘结强度提高,从而有效地提高了复合材料的力学性能。     

Preparation and characterization of EVA–sisal fiber composites

In this work, composites of an EVA polymer matrix and short sisal fiber were characterized. The physical‐morphological as well as chemical interactions between EVA and sisal were investigated. When the samples were prepared in the presence of dicumyl peroxide, the results suggest that crosslinking of EVA as well as grafting between EVA and the sisal fibers took place. Morphological changes were studied by scanning electron microscopy (SEM). Results from Hg‐porosimetry, SEM, Fourier transform infrared spectroscopy, surface free energy, and gel content strongly indicate grafting of EVA onto sisal under the composite preparation conditions, even in the absence of peroxide. The grafting mechanism could not be confirmed from solid‐state ¹³C NMR analysis. The grafting had an impact on the thermal and mechanical properties of the composites, as determined by differential scanning calorimetry and tensile testing. Thermogravimetric analysis results show that the composites are more stable than both EVA and sisal fiber alone. The composite stability, however, decreases with increasing fiber content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1607–1617, 2006     

The effect of trimethylol propane tetraacrylate (TMPTA) and organoclay loading on the properties of electron beam irradiated ethylene vinyl acetate (EVA)/natural rubber (SMR L)/organoclay nanocomposites

Ethylene vinyl acetate (EVA)/natural rubber (SMR L)/organoclay nanocomposites were prepared by melt blending technique with 0–10 phr organoclay loading and 3 phr TMPTA. Electron beam initiated crosslinking on these samples was carried out using a 3.0 MeV electron beam machine with doses ranging from 50 to 200 kGy. XRD results proved that dispersion of organoclay in the nanocomposites was slightly improved by irradiation with TMPTA. This was further supported by transmission electron microscopy images, where the nanoscale dispersion of organoclay was more homogenous throughout the irradiated polymer matrix compared to nonirradiated samples. TMPTA also increased the gel fraction yield, tensile properties and thermal stability of the irradiated neat EVA/SMR L and its nanocomposites. TMPTA was found to act as a crosslink initiator, which promotes crosslink bridges via free radical mechanism in EVA/SMR L matrix. SEM observation shows that the fracture behavior of the irradiated neat EVA/SMR L and its nanocomposites with TMPTA is significantly different compared to the fracture behavior of the nonirradiated neat EVA/SMR L. The distinct failure surface structure formed in the irradiated samples with TMPTA explains the overall higher value of tensile properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal characteristics of ethylene‐co‐vinyl acetate/cellulose microfibers composites

Cellulose microfibers were obtained from Hibiscus sabadariffa by steam explosion technique. Structural and surface analysis of the microfibers showed a reduction in diameter and changes in surface morphology from that of raw fibers. The chemical composition of fibers showed increase in α‐cellulose content and decrease in lignin and hemicelluloses for the microfibers. These factors were further confirmed by XRD, SEM, and FTIR results. The CMF were introduced to EVA at different loading by melt extrusion. The composites were analyzed for their thermal stability and phase transition using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA analysis of the composites showed increased onset temperatures for composites compared with pure EVA indicating the superior thermal stability of the composites with fiber loading. DSC analysis shows increase in melting enthalpy and percentage crystallinity with fiber loading increases. Kinetic parameter for the degradation of the composites was obtained using Broido, Coats–Redfern, and Horowitz‐Metzger methods. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

动态硫化EVA/BR热塑性弹性体的增强研究

采用动态硫化法制备了乙烯-醋酸乙烯共聚物(EVA)/顺丁橡胶(BR)共混型热塑性弹性体(TPE),通过在树脂相中添加HDPE的方式对复合体系进行增强,对其力学性能及断面微观结构进行了研究。结果表明,对于动态硫化EVA/BR共混型TPE,当HDPE填充量在0～30phr的范围内,其动态硫化产物均表现出TPE的特征;随着树脂相中HDPE用量的提高,复合体系的拉伸强度、撕裂强度、邵氏硬度趋于显著提高,断裂伸长率趋于缓慢增加,而扯断永久形变则始终低于25%;FE-SEM的观察表明,动态硫化TPE的拉伸断面上两相界面结合良好;刻蚀样品表面的硫化胶粒子的尺寸在5mm左右且均匀分散。     

LDPE/EVA/SEBS发泡材料的研究

将苯乙烯-乙烯／丁烯-苯乙烯共聚物（SEBS）应用于低密度聚乙烯（LDPE）／乙烯-醋酸乙烯共聚物（EVA）发泡材料中。讨论了SEBS用量、SEBS充油量对LDPE／EVA发泡材料性能的影响。并且讨论了发泡剂偶氮二甲酰胺（AC）、交联剂过氧化二异丙苯（DCP）、填料微细重质碳酸钙（CaCO3）用量对LDPE／EVA／SEBS发泡材料性能的影响。对发泡前样品,用溶剂将脆性断面的SEBS相区刻蚀掉,通过SEM对样品的观察发现,SEBS在树脂中分散比较均匀。通过SEM对发泡前样品脆性断面的观察发现,CaCO3在树脂中分散比较均匀。通过SEM对发泡样品的切断面观察发现,泡孔比较均匀。     

Effects of an (Intumescent flame retardant)‐montmorillonite combination on the thermal stability and fire‐retardant properties of LDPE/EVA nanocomposites

The combined effects of an organically modified montmorillonite (OMMT) and an intumescent flame retardant, poly (piperazine spirocyclic pentaerythritol bisphosphonate) (PPSPB), in (low‐density polyethylene)/[ethylene‐(vinyl acetate) copolymer] (LDPE/EVA) nanocomposites were observed. The results from X‐ray diffraction and transmission electron microscopy studies showed that exfoliated LDPE/EVA/PPSPB/OMMT nanocomposites were formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis and cone calorimeter tests. The combination of PPSPB and montmorillonite improved thermal stability and reduced significantly the flammability, including peak heat release rate (PHRR), total heat release, average mass loss rate, etc. The PHRR of LDPE/EVA/PPSPB/OMMT was reduced by about 50% compared to that of an LDPE/EVA blend. The morphology and composition of the residues generated by cone calorimeter tests were investigated by scanning electronic microscopy (SEM) and energy dispersive X‐ray (EDX) analysis. The results of SEM showed that a compact and dense intumescent char was formed from the LDPE/EVA/PPSPB/OMMT nanocomposite upon combustion. The results of EDX examination revealed that the carbon content of this char was increased significantly by the combined effect of PPSPB and montmorillonite. J. VINYL ADDIT. TECHNOL., 19:285–292, 2013. © 2013 Society of Plastics Engineers