PP-g-(MAH/St)和PP-g-MAH对聚丙烯/木粉复合材料性能的影响

在转矩流变仪中用熔融接枝法制备马来酸酐(MAH)和苯乙烯(St)接枝聚丙烯（PP）-PP-g-(MAH/St)和PP-g-MAH,将其作为聚丙烯/木粉复合材料的相容剂。 FTIR证实MAH和St单体与PP发生接枝反应。 用SEM和DSC等手段考察两种相容剂对PP/木粉复合材料微观形貌和结晶性能的影响,探索了各种PP/木粉复合材料加工和力学性能不同的内在原因。 SEM显示,PP-g-(MAH/St)改性木粉比PP-g-MAH改性木粉在PP基体中分散性更佳,木粉与PP的界面更加模糊,相容性进一步改善。 DSC结果表明,PP-g-(MAH/St)改性体系可增强木粉对PP的异相成核作用,提高结晶温度和结晶度。 复合材料的加工和力学性能测试结果表明,PP-g-(MAH/St)改性效果明显优于PP-g-MAH。 复合材料的熔体质量流动速率随相容剂用量的增加而逐步下降,PP-g-(MAH/St)改性体系拉伸强度和弯曲强度却逐步上升,并在相容剂用量为4.8 g/100 g PP时达到极值。 此时其拉伸强度达40.62 MPa,分别是未改性体系和PP-g-MAH改性体系的1.29和1.17倍;其弯曲强度达45.72 MPa,分别是未改性体系和PP-g-MAH改性体系的1.23和1.59倍;而无缺口冲击强度却在相容剂用量为3.6 g/100 g PP时达到极值13.35 kJ/m2,分别是未改性体系和PP-g-MAH改性体系的1.62倍和1.42倍。     

改性小麦秸秆粉/聚丙烯复合材料的性能研究

研究了碱处理(AT)、苯甲酸(BA)或/和硬脂酸(SA)改性对小麦秸秆粉(WSP)/聚丙烯(PP)复合材料(WSP/PP-CM)力学性能、热稳定性能、流变性能、润湿性能和吸水性能的影响。结果表明:碱处理可提高WSP/PP-CM的拉伸强度(TS)、弯曲强度(FS)、冲击强度(IS)、起始热分解温度(T_i)和接触角(θ),而使平衡扭矩(BT)和吸水率(WU)减小,因为AT使得WSP表面活性增加、疏水性增强。在AT基础上再进行BA或者SA改性,WSP/PP-CM的TS、FS、IS及T_i继续提高,BT进一步降低;在AT基础上再进行BA/SA复合改性,WSP/PP-CM的TS、FS、IS及T_i大幅提高了41.21%、32.02%、38.68%和35.7℃,BT进一步下降至9.7N·m。AT后再进行BA或/和SA改性,复合材料的疏水性虽然优于未改性WSP/PP-CM,但效果均不及单纯的AT。     

复合改性竹纤维/聚丙烯复合材料的制备与性能研究

为改善竹纤维(BF)与聚丙烯(PP)的界面结合,采用碱(NaOH)和异氰酸酯偶联剂(TDI)复合改性竹纤维,制备BF/PP复合材料。分析了竹纤维改性前后主要化学成分、热行为及化学结构变化,考察了竹纤维改性对复合材料维卡软化点(VSP)和动态热力学性能影响,用扫描电镜对复合材料断面进行了观察,最后探讨了改性竹纤维添加量对复合材料力学性能的影响。结果表明:BF经复合改性后,表面形成了氨酯键结构,竹纤维素晶体尺寸和结晶度增大,竹纤维的最快热降解温度和复合材料的VSP分别提高了20℃和4.5℃。SEM、DMA分析显示,竹纤维复合改性改善了两相界面结合,利于力学性能提高。拉伸实验表明,在复合改性竹纤维添加比例为40%时,复合材料综合性能最佳,其冲击强度、拉伸强度和弯曲强度分别增加了21.6%、23.3%和27.8%,拉伸模量和弯曲模量分别增加了24.2%和30.4%。     

复合改性竹纤维/聚丙烯复合材料的制备与性能研究北大核心CSCD

为改善竹纤维(BF)与聚丙烯(PP)的界面结合,采用碱(NaOH)和异氰酸酯偶联剂(TDI)复合改性竹纤维,制备BF/PP复合材料。分析了竹纤维改性前后主要化学成分、热行为及化学结构变化,考察了竹纤维改性对复合材料维卡软化点(VSP)和动态热力学性能影响,用扫描电镜对复合材料断面进行了观察,最后探讨了改性竹纤维添加量对复合材料力学性能的影响。结果表明:BF经复合改性后,表面形成了氨酯键结构,竹纤维素晶体尺寸和结晶度增大,竹纤维的最快热降解温度和复合材料的VSP分别提高了20℃和4.5℃。SEM、DMA分析显示,竹纤维复合改性改善了两相界面结合,利于力学性能提高。拉伸实验表明,在复合改性竹纤维添加比例为40%时,复合材料综合性能最佳,其冲击强度、拉伸强度和弯曲强度分别增加了21.6%、23.3%和27.8%,拉伸模量和弯曲模量分别增加了24.2%和30.4%。     

原位固相接枝改性碳酸钙/聚丙烯复合材料的制备

用马来酸酐（MAH）在碳酸钙（CaCO3）表面引入双键,通过原位固相接枝法将聚丙烯蜡（PPW）化学键合在CaCO3表面,制得3种接枝率的CaCO3-MAH-PPW。 将这3种改性CaCO3填充聚丙烯（PP）制备复合材料,研究了PP/CaCO3界面作用对复合材料强度的影响。 结果表明,CaCO3表面经PPW接枝改性后在PP中的分散性提高,与PP相容性变好;随着改性CaCO3表面PPW接枝率的提高,CaCO3与PP之间界面作用逐渐增强。 当PPW接枝率为4.48 mg PPW/g CaCO3时,CaCO3与PP之间的界面作用最强,复合材料拉伸强度下降最小,杨氏模量提升最大,当m(PP)∶m(CaCO3)=100∶50时,杨氏模量达0.86 GPa,是纯PP的1.63倍;而PPW化学接枝率为2.49 mg PPW/g CaCO3时,CaCO3与PP之间的界面作用适中,复合材料缺口冲击强度提升最大,且当m(PP)∶m(CaCO3)=100∶10时,缺口冲击强度达3.91 kJ/m2,是纯PP的1.35倍。     

PP/EPDM/CaCO_3三元复合材料的相结构及力学性能研究

采用以化学键合方式在CaCO3表面包覆上聚丙烯蜡和将改性后的CaCO3先与EPDM复合、再与PP复合的工艺,制备PP/EPDM/CaCO3三元复合材料,以期在PP基体材料中得到EPDM包裹CaCO3的相结构.通过测量三元复合体系中各组分的表面张力,计算各可能组分对之间的界面张力和黏结功,分析三元复合体系中可能的相结构.热力学计算结果表明,三元复合体系中既存在以EPDM为壳、CaCO3为核的"核壳结构",又存在CaCO3与EPDM各自独立分散在PP基体中的结构.电镜照片进一步揭示,在PP/EPDM/改性CaCO3三元复合体系与PP/EPDM/未改性CaCO3三元复合体系中,这两种相结构的比例是不同的,在前者中以核壳结构为主.CaCO3表面性质的不同是产生这一差别的原因.由于这一结构差别的存在,PP/EPDM/改性CaCO3三元复合体系比PP/EPDM/未改性CaCO3三元复合体系具有更好的力学性能.当EPDM用量为8 phr、改性CaCO3用量为15 phr时,三元复合体系的冲击强度达14.25 kJ/m2,是纯PP的3.17倍.     

聚丙烯/纳米级金红石型二氧化钛/聚烯烃弹性体复合材料的抗老化性能研究

采用TEM和UV-Vis等测试手段表征了金红石型纳米级TiO2和体相TiO2的性能特征;通过熔融共混法分别制备了PP/纳米级TiO2/POE和PP/体相TiO2/POE复合材料,采用GB/T16422·2-1999所述的塑料实验室光源暴露实验方法,用氙灯气候试验机对纯PP和复合材料进行28天人工加速老化.结果表明,二氧化钛粒子在PP/POE基体中分散性良好,而纳米粒子对PP/POE基体具有增韧作用;改性后的两类复合材料均具有优异的抗老化性能,而PP/(1·0wt%)纳米级TiO2/POE复合材料的抗老化性能更加优异,其加速老化28天后的无缺口冲击强度达到80·45kJ·m-2,比纯PP提高4倍多,而同期加速老化28天后的PP/(1·0wt%)体相TiO2/POE复合材料的无缺口冲击强度只有47·88kJ·m-2;对纯PP老化过程中的羰基指数和冲击性能的变化情况进行了分析,发现二者近似成线性关系,其相关系数r在0·9以上.     

不同改性剂对聚丙烯/碳酸钙复合材料性能的影响

以马来酸酐(MAH)、聚丙烯蜡(PPW)为主要原料,采用原位固相接枝改性法制得PP/CaCO3-MAH-PPW复合材料,并与添加相容剂聚丙烯接枝马来酸酐(PP-g-MAH)所制得的PP/PP-g-MAH/CaCO3复合材料进行比较。结果表明,CaCO3良好的分散性及其与PP基体适宜的界面粘接是复合材料具有较好韧性的关键因素。与PP/PP-g-MAH/CaCO3复合材料相比,PP/CaCO3-MAH-PPW复合材料表现出更佳的冲击、弯曲和加工性能,当m(PP)∶m(CaCO3)=100∶20时,材料缺口冲击强度达到最大值,是基体树脂的1.19倍。     

PP-g-MAH对聚丙烯/滑石粉复合材料的性能影响

研究了两种马来酸酐接枝聚丙烯（PP-g-MAH）在不同含量时对聚丙烯（PP）/滑石粉复合材料的力学性能、雾化性能和线性膨胀系数的影响.结果表明,接枝物的加入能提高复合材料的拉伸性能、冲击性能和弯曲性能,但随着含量的增加拉伸强度、冲击强度和弯曲强度及弯曲模量有所降低.在含量相同时,接枝物1对冷凝组份的影响更小.复合材料的线性膨胀系数随接枝物含量的增加先减小后增加.     

聚氯乙烯/木纤维复合材料的研究Ⅰ.硬脂酸和ABS改性木纤维对复合材料力学性能的影响

为改善聚氯乙烯（PVC）和木纤维两者的界面亲合性，提高PVC／木纤维复合材料的机械力学性能，分别用硬脂酸和ABS来改性木纤维的表面，研究发现用硬脂酸处理木纤维可提高复合材料的拉伸强度，但对复合材料的冲击强度影响不大．ABS处理木纤维可同时提高复合材料的拉伸强度和冲击强度。本文也研究了改性剂用量和木纤维含量对复合材料力学性能的影响。     

New PP/PLA/cellulose composites: effect of cellulose functionalization on accelerated weathering behavior (accelerated weathering behavior of new PP/PLA/cellulose composites)

Polylactic acid (PLA) was used as partial replacement for conventional thermoplastic matrix, new composites comprising cellulose, polypropylene (PP), and PLA being realized. In order to obtain a compatible interface between cellulosic pulp and polymeric matrix, two chemical modifications of cellulose with stearoyl chloride and toluene di‐isocyanate (TDI) were performed, structural changes being evidenced by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The composite materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic scanning calorimetry, impact, tensile and melt rheological tests, surface tension, and dynamic vapor sorption. Because promising results for impact strength and Young modulus were recorded when replacing 15% of PP with PLA in blends of PP with the same cellulosic pulp load, the aim of our study was to assess the behavior to accelerate weathering of composites comprising PP, cellulosic pulp, and PLA. Although the slight decrease in the mechanical properties was recorded after accelerated weathering, the use of functionalized cellulose successfully prevented the deterioration of surface materials, especially for composite comprising stearoyl chloride treated cellulose pulp. Copyright © 2015 John Wiley & Sons, Ltd.     

羟基不饱和脂肪酸改性纳米碳酸钙对聚丙烯微观形态和流变性能的影响

采用羟基不饱和脂肪酸,通过固相法对硬脂酸改性的工业纳米碳酸钙CCR进行表面改性制备了R-CCR,红外光谱(FTIR)显示改性剂已结合在碳酸钙表面.通过熔融共混法制备了聚丙烯(PP)/乙丙橡胶(EPDM)/纳米碳酸钙二元和三元复合材料.并利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察复合材料的微观形态,发现R-CCR的加入,使PP复合材料的拉伸断面出现明显的拉丝状结构和大面积的屈服变形,与PP/EPDM/CCR相比,PP/EPDM/R-CCR冲击断面的空穴明显增加并细化,R-CCR在PP基体中分散均匀,且界面模糊,与基体的相容性明显优于CCR.复合材料流变行为的研究表明R-CCR的加入,体系储存模量G′和损耗模量G″随频率的增加而增加,对损耗因子和复数粘度的影响不大;但PP/EPDM/R-CCR复合材料的表观粘度,明显低于PP/EPDM/CCR和纯PP,同时,剪切速率的增加可有效降低体系的表观粘度.力学性能表明,R-CCR对PP同时起到增韧和增强的效果.且R-CCR和EPDM对PP具有协同增韧的效果.在保持聚丙烯的模量和强度基本不变的前提下,大幅度的改善聚丙烯的韧性,同时加工性能保持不变.     

The influence of KH-550 on properties of ammonium polyphosphate and polypropylene flame retardant composites

Ammonium polyphosphate (APP)/polypropylene (PP) composites were prepared by melt blending and extrusion in a twin-screw extruder. APP was first modified by a silane coupling agent KH-550 then added to polypropylene. The surface modification of APP by the coupling agent decreased its water solubility and its interface compatibility with the PP matrix. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) were used to characterize the flame retardant property and the thermal stability of the composites. The addition of APP improved the flame retardancy of PP remarkably. The crystal structures of APP/PP composites were characterized by X-ray diffraction (XRD). The results indicated that β-crystal phase PP may be formed. The structures and morphologies of APP, KH-550/APP and APP/PP composites were characterized by field-emission scanning electron microscope (FESEM). The mechanical property tests showed good mechanical properties of composite materials. Compared with unmodified one, the impact strength, tensile strength and elongation of modified APP/PP were all improved.     

纳米级金红石型二氧化钛与受阻胺光稳定剂协同改进ABS的抗老化性能研究

分别采用纳米级金红石型TiO2和受阻胺光稳定剂(HALS)对ABS进行改性,通过熔融共混法制备了ABS/纳米TiO2、ABS/纳米TiO2/HALS和ABS/HALS复合材料,采用GB/T16422.2~1999所述的塑料实验室光源暴露实验方法,用氙灯气候试验机对其进行28天人工加速老化,通过测定其老化过程中的无缺口和缺口试样冲击强度的变化来对其抗老化性能进行表征,同时利用光学显微镜和扫描电镜对其老化过程中的冲击断口形貌变化进行了研究.结果表明,纳米TiO2在ABS基体中分散良好,改性后的复合材料均具有较好的抗老化性能,纳米TiO2与HALS复合改性ABS对其耐候性的提高具有明显的协同作用,其老化后的抗冲击性能超过了单一使用HALS或纳米TiO2的改性效果,老化28天后纯ABS树脂试样的无缺口冲击强度保持率只有20%左右,添加2.0 wt%纳米TiO2后,老化28天后的ABS/纳米TiO2/HALS复合材料试样的保持率则提高到47.9%,为纯ABS树脂试样的2.5倍.     

Effect of Silane Coupling Agent and Compatibilizer on Properties of Short Rossells Fiber/Poly(propylene) Composites

Rossells fiber reinforced polypropylene composites were prepared by melt mixing. The fiber content was 20 wt%. Octadecyltrimethoxysilane (OTMS) and maleic anhydride grafted polypropylene (MAPP) were used to improve the adhesion between poly(propylene) (PP) and the fiber. The mechanical, rheological, and morphological properties, and heat distortion temperature (HDT) of the composites were investigated. Tensile strength, impact strength, flexural strength and HDT of MAPP modified PP composites increased with an increase in MAPP content. However, no remarkable effect of MAPP content on the Young's modulus of the composites was found. OTMS resulted in small decreases of tensile strength and Young's modulus, and increase in impact strength. Scanning electron micrographs revealed that MAPP enhanced surface adhesion between the fiber surface and PP matrix.     

Effect of unsaturated hydroxyl-fatty acid modified nano-CaCO3 on the morphological and rheological behavior of PP

A modified nano-calcium carbonate (R-CCR) was prepared by coating a layer of unsaturated hydroxylfatty acid on the surface of CCR powders using a solid state method; the latter were commercial nano-CaCO₃ modified with stearic acid. FTIR studies indicate that the modifier is combined on the surface of CaCO₃. PP/EPDM/nano-CaCO₃ ternary composites were prepared by a melt-mixing method. SEM and TEM were utilized to examine the morphology of the composites. The tensile fractured surface of PP/EPDM/R-CCR showed a fibroid morphology and large-scale yield deformation. The impact fractured surface showed that the amount of cavities in the PP/EPDM/R-CCR system was increased, however their size diminished obviously. R-CCR particles were dispersed uniformly in the PP matrix, and their compatibility was distinctly improved as compared to CCR when the amount of R-CCR was 15 h⁻¹. The tensile strength remained nearly constant (reduced from 27.6 MPa to 27.5 MPa), while the impact strength increased from 9.6 kJ/m² to 15.4 kJ/m² as CCR was replaced by R-CCR. Meanwhile, the bending strength and bending modulus also increased correspondingly. Furthermore, the impact strength of PP/EPDM/R-CCR was maintained at a high level (15.4 kJ/m²), which was more than the sum of that of PP/EPDM and PP/R-CCR (6.6 kJ/m² and 6.1 kJ/m² respectively). This indicates that the R-CCR and EPDM have a significant synergistic toughening effect on PP while maintaining the strength and modulus of virgin PP. Both the storage modulus G′ and loss modulus G″ of PP/EPDM and PP/EPDM/R-CCR composites increase with increasing frequency, but the values of G′ and G″ of the tertiary composite are relatively higher than those of the binary system. The loss factor and viscosity decrease with increasing frequency, but there is little difference between tertiary and binary composites. The apparent viscosity η of the tertiary system containing R-CCR is lower than that of the tertiary system containing CCR and virgin PP. The viscosity of the composites sig-nificantly decreases with increasing shear rate. The mea-sured mechanical properties of the composites indicate that replacing CCR with R-CCR for binary composites could simultaneously enhance the toughness and strength of PP. __________ Translated from Acta Polymerica Sinica, 2008, 4 (in Chinese)     

Simultaneous enhancement of electrical conductivity and impact strength via formation of carbon black‐filler network in PP/EPDM Blends

The electrical conductivity and impact strength of polypropylene(PP)/EPDM/carbon black ternary composites were investigated in this paper. Two processing methods were employed to prepare these ternary composites. One was called one‐step processing method, in which the elastomer and the filler directly melt blended with PP matrix. Another one was called two‐step processing method, in which the elastomer and the filler were mixed first, and then melt blended with pure PP. To get an optimal phase morphology that favors the electrical conductivity and impact strength, controlling the distribution of CB in PP/EPDM blend was a crucial factor. Thus the interfacial tension and the work of adhesion were first calculated based on the measurement of contact angle, and the results showed that CB tended to be accumulated around EPDM phases to form filler‐network structure. Expectably, the filler‐network structure was observed in PP/EPDM/CB(80/20/3) composite prepared by two‐step processing method. The formation of this filler‐network structure decreased the percolation threshold of CB particles in polymer matrix, and the electrical conductivity as well as Izod impact strength of the composite increased dramatically. This work provided a new way to prepare polymer composites with both improved conductivity and impact strength. Copyright © 2009 John Wiley & Sons, Ltd.