A study of PP/PET composites: Factorial design,mechanical and thermal properties

Due to the economic importance of polypropylene (PP) and polyethylene terephthalate (PET), and the large amount of composites made with PP matrix and recycled PET as reinforcing material; an investigation was performed regarding the mechanical and thermal behavior of PP composites containing recycled polyethylene terephthalate fibers (rPET). Interfacial adhesion between the two materials was achieved by adding a compatibilizer, maleic anhydride grafted polypropylene, PP-g-MA. Mechanical behavior was assessed by tensile, flexural, impact and fatigue tests, and thermal behavior by HDT (Heat Deflection Temperature). Fractured surfaces and fiber were investigated by scanning electron microscopy. Multiple regression statistical analysis was performed to interpret interaction effects of the variables. Tensile strength, tensile modulus, flexural strength, flexural modulus and HDT increased after rPET fiber incorporation while strain at break, impact strength and fatigue life decreased. Addition of compatibilizer increased tensile strength, flexural strength and flexural modulus, fatigue life and HDT while tensile modulus, strain at break and impact strength decreased. However, at low fiber content, the impact strength increased, probably due to nucleation effects on PP.     

Effect of long fiber thermoplastic extrusion process on fiber dispersion and mechanical properties of viscose fiber/polypropylene composites

Viscose fiber reinforced polypropylene (PP/VF) composites were manufactured using long fiber thermoplastic (LFT) extrusion techniques with two different methods namely LFT‐l and LFT‐2. The compatibilizer [maleated polypropylene (MAPP)] and dispersing agent [stearic acid (SA)] were added to the PP/VF in order to improve the fiber dispersion and interfacial adhesion. The PP/VF composites manufactured using LFT‐2 showed better fiber dispersion with higher tensile and flexural properties compared to the composites manufactured using LFT‐1 method. Similarly, the impact strength and toughness of the LET‐2 composites showed an improvement of 36 and 20% than LFT‐1 whereas the average fiber length of composites was decreased from 6.9 mm to 4.4 mm because of the increase in shear energy as a result of residence time. Further, the addition of SA and MAPP to LFT‐2 process has significantly improved the fiber dispersion and mechanical performance. The fiber dispersion and fracture behavior of the LFT‐1 and LFT‐2 composites were studied using scanning electron microscopy analysis. The Fourier transformation infrared spectra were also studied to ascertain the existence of type of interfacial bonds. Copyright © 2015 John Wiley & Sons, Ltd.     

动态固化聚丙烯/环氧树脂共混物的研究

将动态硫化技术应用于热塑性树脂 热固性树脂体系 ,制备了动态固化聚丙烯 (PP) 环氧树脂共混物 .研究了动态固化PP 环氧树脂共混物中两组分的相容性、力学性能、热性能和动态力学性能 .实验结果表明 ,马来酸酐接枝的聚丙烯 (PP g MAH)作为PP和环氧树脂体系的增容剂 ,使分散相环氧树脂颗粒变细 ,增加了两组分的界面作用力 ,改善了共混物的力学性能 .与PP相比 ,动态固化PP 环氧树脂共混物具有较高的强度和模量 ,含 5 %环氧树脂的共混物拉伸强度和弯曲模量分别提高了 30 %和 5 0 % ,冲击强度增加了 15 % ,但断裂伸长率却明显降低 .继续增加环氧树脂的含量 ,共混物的拉伸强度和弯曲模量增加缓慢 ,冲击强度无明显变化 ,断裂伸长率进一步降低 .动态力学性能分析 (DMTA)表明动态固化PP 环氧树脂共混物是两相结构 ,具有较高的储能模量 (E′)     

Mechanical properties and morphological structures of short glass fiber reinforced PP/EPDM composite

The mechanical properties and crystal morphological structures of short glass fiber (SGF) reinforced dynamically photo-irradiated polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) composites were studied by mechanical tests, wide-angle X-ray diffraction (WAXD), optical microscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). The mechanical properties of PP/EPDM composites, especially the tensile strength were greatly strengthened by dynamically photo-irradiation and the incorporation of SGF. The results from the WAXD, SEM, DSC, and TGA measurements reveal: (i) the formation of β-type crystal of PP in the PP/EPDM/SGF composite; (ii) the fiber length in dynamically photo-irradiated PP/EPDM/SGF composites are general longer than that in corresponding unirradiated samples. The size of EPDM phase in the photo-irradiated composites reduces obviously whereas the droplet number increases; (iii) photo-irradiation improves the interface adhesion between SGF and polymer matrix; (iv) the melting and crystallization temperatures of the photo-irradiated composites are not affected greatly by increasing the SGF content; (v) the thermal analysis results show that the incorporation of SGF into PP/EPDM plays an important role for increasing its thermal stability.     

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 compatibilisers on mechanical and thermal properties of bentonite filled polypropylene composites

Bentonite filled polypropylene composites were prepared using a Polydrive Thermo Haake, internal mixer at 180 °C and at 50 rpm of rotor speed. Effect of compatibilisers on mechanical, thermal, water absorption and morphological properties of bentonite filled polypropylene composites was investigated. Two types of compatibilisers namely, palm oil fatty acid additive (POFA) and polypropylene grafted-maleic anhydride (PPMAH) have been used in this study. The mixing of the composites improved with the addition of POFA. The impact strength and elongation at break increased with the presence of both compatibilisers whilst, tensile strength and Young's modulus improved only with addition of PPMAH. Morphological investigation using SEM revealed that the improvement in impact strength and elongation at break was due to enhancement of the interfacial adhesion between bentonite and PP. The thermal stability of bentonite filled PP improved with the incorporation of POFA and PPMAH. Less percentage of water absorption has been observed in PP-bentonite system with PPMAH.     

纳米CaCO_3/相容剂/PP中的界面相互作用研究

采用不同相容剂(PP-g-MAH、POE-g-MAH和EVA-g-MAH)制备了不同界面相互作用的纳米CaCO3(CC)/相容剂/PP体系,研究了相容剂/PP和相容剂/CC界面相互作用对PP/CC的结晶形态、结晶行为、熔融特性和力学性能的影响.观察到PP/CC界面相互作用提高PP结晶温度和PP/CC的模量和冲击强度,但降低了屈服强度.相容剂/CC界面相互作用进一步提高了PP/CC的结晶温度.PP/相容剂界面相互作用取决于PP与相容剂相容性.PP/PP-g-MAH相容性高有利于提高PP/CC的异相成核作用和PP/CC屈服强度和模量,但降低冲击强度.PP/POE-g-MAH部分相容对相容剂/CC界面的异相成核作用、PP/CC屈服强度和模量影响不大,可明显提高冲击强度.但PP/EVA-g-MAH不相容导致PP/CC冲击强度明显降低.     

Tensile and flexural properties of polypropylene composites filled with highly effective flame retardant magnesium hydroxide

The reinforcing effects of highly effective flame retardant magnesium hydroxide (FMX) content on the tensile and flexural properties of filled polypropylene (PP) composites were investigated within the FMX weight fraction range from 5 to 60 wt%. It was found that the Young's modulus and flexural modulus increased approximately linearly while the tensile yield strength and tensile fracture strength decreased slightly with increasing the FMX weight fraction. When the FMX weight fraction was lower than 20%, the tensile elongation at break decreased considerably, and then decreased slightly; the flexural strength increased when the FMX weight fraction was lower than 30%, and then decreased slightly. The tensile properties increased with increasing rate of tension. Moreover, the tensile yield strength of the composites was estimated using an equation proposed in previous work, and good agreement was shown between the predicted and the measured data.     

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.     

POE改性高熔指聚丙烯性能研究

采用聚烯烃弹性体(POE)对高熔指聚丙烯(PP)进行共混改性,研究了弹性体POE的含量对高熔指PP的力学性能、流动性和成型收缩率的影响规律。结果表明:随着弹性体POE含量的增加,共混材料的悬臂梁缺口冲击强度增大,断裂拉伸应变增大,弯曲强度、弯曲模量降低,拉伸强度降低,流动性变差,收缩率减小。     

Mechanical properties and morphology for polypropylene composites filled with microencapsulated red phosphorus

The effects of the microencapsulated red phosphorus (MRP) content and specimen thickness on the mechanical properties of the filled polypropylene (PP) composites were studied at room temperature. The results showed that the influence of the MRP on the tensile and impact properties of the composites was significant, and the Young's modulus and impact strength of the composites increased nonlinearly while the tensile strength decreased slightly with increasing the MRP weight fraction; the tensile elongation at break increased outstandingly when the MRP weight fraction was less than 2% and then decreased with increasing the MRP weight fraction. Furthermore, the impact fracture surface was examined by scanning electronic microscope. The results suggested that the toughening effect was attributed to the absorption of impact fracture energy by the microencapsulated layer. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimization of aramid powder reinforced PP/EPDM blends

The effect of twaron powder on the tensile behavior and abrasion resistance of polypropylene (PP) and an ethylene‐propylene diene terpolymer (EPDM) and their blends has been investigated by means of an experimental design. The stiffness and strength of the composites with EPDM as continuous phase hardly varies with the addition of twaron powder, however, at high percentages of PP (above 50%) in the matrix, these properties decrease as powder content increases. In all cases the elongation at fracture decreases in the presence of the powder. A maximum in the abrasion resistance is observed in the 14% twaron powder filled polypropylene composite. From the results and the graphs of the response surfaces a better affinity between the twaron powder and the EPDM can be suggested. It can be also deduced that as twaron content in the composite increases, the phase inversion in the polymer matrix takes place at lower PP percentages. A good correlation between mechanical characteristics and morphological observations has been observed.     

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.     

Crystallization and mechanical properties of basalt fiber-reinforced polypropylene composites with different elastomers

In this study, composites based on polypropylene (PP), basalt fiber (BF), polypropylene-graft-maleic anhydride (MAPP) and different elastomers were manufactured by extrusion compounding and injection molding. The main focus of this study was to comparatively investigate the effect of three kinds of elastomers (ethylene–propylene–diene monomer (EPDM), polyethylene–octene (POE) and ethylene–vinyl–acetate (EVA)) on non-isothermal crystallization and mechanical properties of the composites with various BF contents. The tensile test results showed that BF had a reinforcing effect on PP resin, and the addition of MAPP further improved the tensile properties by the enhancement of PP/BF interfacial bonding. Among the elastomers, EPDM was more effective in improving the tensile strength and tensile modulus, while POE significantly toughened the impact strength. Micrographs of scanning electron microscope on the impact fracture surfaces indicated a good dispersion by the addition of POE and EPDM, while some agglomerations were observed in the presence of EVA. The non-isothermal crystallization kinetics were investigated based on Avrami and Mo equations at six different cooling rates by using differential scanning calorimetry. Micrographic images of polarized optical microscopy showed that the spherulite size of PP reduced in the presence of EPDM and EVA.     

Dynamically vulcanized ethylene propylene diene terpolymer/nylon thermoplastic elastomers

A thermoplastic elastomer (TPE) of ethylene propylene diene terpolymer (EPDM) and nylon with excellent mechanical properties was prepared by dynamic vulcanization. The effects of the curing systems, compatibilizer, nylon content and reprocessing on the mechanical properties of EPDM/nylon TPEs were investigated in detail. Experimental results indicate that maleic anhydride (MAH) grafted EPR has a better performance in compatibilizing the EPDM/nylon blends compared with other compatibilizers containing acid group. Tensile strength and elongation at break go through a maximum value at a compatibilizer resin content (on total rubber dosage) of 20%. EPDM/nylon TPE using sulfur as curative has higher tensile strength and elongation than that of TPE using phenolic resin or peroxide as curatives. Tensile strength and elongation at break increase with increasing nylon content. Scanning electron microscopy results show that rubber particles distributed at an average size of 1 μm in dynamic vulcanized EPDM/MAH-g-EPR/nylon TPE.     

Mechanical properties and characteristic of surface treated bamboo fiber reinforced PP/PS blends

Bamboo fiber (BF) as organic filler is characterized by mechanical properties analysis and morphology examination for polypropylene (PP) and polystyrene (PS) matrix blends. Effects of different filler content on tensile strength, flexural properties, and impact strength are proposed. It is observed from scanning electron microscopy (SEM) studies that addition of BF is beneficial in increasing mechanical strength via increasing the interface dispersed phase. The optimum tensile properties and impact properties of BF content were at 40 wt% for PP/PS/BF composite on melt mixing conditions. The results showed a significant improvement in mechanical properties of PP/PS/BF ternary blend composite. Comparing with untreated BF, content of carbon and nitrogen of treated BF decreased to 66.57 and 2.31%, oxygen content increased to 21.07%, and silicon content increased from 0 to 10.04%. The element ratio of O/C, N/C, and Si/C changed to 31.65, 3.47, and 15.08, respectively.     

Rheological,morphological and mechanical properties of flax fiber polypropylene composites: influence of compatibilizers

In this work, the rheological, mechanical and morphological properties of flax fiber polypropylene composites were investigated. The effect of incorporating a polypropylene grafted acrylic acid or a polypropylene grafted maleic anhydride on these properties has been studied as well. According to scanning electron microscopic observations and tensile tests, the addition of a compatibilizer improved the interfacial adhesion between the flax fibers and the polymer matrix. The tensile modulus of composite containing 30 wt% flax fibers was improved by 200 % and the tensile strength improved by 60 % in comparison with the neat PP. Plasticizing effect of the compatibilizers as a result of their lower melt flow index was also shown to decrease the rheological properties of the composites, even though the effect was not pronounced on the mechanical properties.     

Preparation of polypropylene/ethylene‐propylene‐diene terpolymer/nitrile rubber ternary thermoplastics vulcanizates with good mechanical properties and oil resistance by core‐shell dynamic vulcanization

As the most successful commercialized thermoplastic vulcanizates (TPVs), polypropylene (PP)/ethylene propylene rubber (EPDM) TPVs exhibit poor oil resistance. In this work, we prepared PP/EPDM/butadiene acrylonitrile rubber (NBR) ternary TPVs with good oil resistance using core‐shell dynamic vulcanization. According to the theoretical analysis of the spreading coefficient and the transmission electron microscopy results, the rubber phases exhibited a special core‐shell structure, in which the cross‐linkedNBR‐core was encapsulated by the EPDM‐shell. The core‐shell structure effectively improved the interfacial compatibility between PP and NBR phase as the EPDM‐shell could avoid the direct contact of them, thus improving the mechanical properties of the TPVs. For example, the PP/EPDM/NBR (40/30/30) ternary TPV showed enhanced tensile strength of 12.57 MPa, compared with 10.71 MPa of PP/EPDM (40/60) TPV and 11.11 MPa of PP/NBR (40/60) TPV, respectively. Moreover, the oil resistance of the TPVs was also improved. Compared with PP/EPDM TPV, the change rates in mass, volume, tensile strength and elongation at break of PP/EPDM/NBR TPV after oil immersion decreased by 42.18%, 48.69%, 52.68% and 28.77%, respectively.     

多单体接枝聚丙烯对PBT/PP共混体系的形态结构及力学性能影响研究

研究了甲基丙烯酸缩水甘油酯 (GMA)和苯乙烯 (St)多单体熔融接枝聚丙烯 (PP g (GMA co St) )对聚对苯二甲酸丁二酯 (PBT) 聚丙烯 (PP)共混物的形态结构和力学性能的影响 .利用双螺杆挤出机对PBT PP合金进行共混挤出 ,使用DSC、FT IR和SEM、TEM等手段对共混物进行了分析和相形态观察 ,并测试了力学性能 .实验证明 ,熔融共混过程中PP g (GMA co St)的环氧基团可以与PBT的端羧基发生化学反应 ,就地生成了PBT g PP共聚物 ,该共聚物可对PBT PP合金起到良好的增容剂作用 ,使共混物的相区尺寸显著减小 ,共混物的拉伸强度和冲击强度等力学性能同时得到明显改善 ,达到了弹性体系或小分子增容所难以达到的力学性能平衡的效果 .此外 ,TEM的研究还在PBT PP g (GMA co St)共混物中发现了特殊的微相分离结构     

Tailoring of interface of polypropylene/polystyrene/carbon nanofibre composites by polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene

Mechanical and physical properties of polypropylene (PP)/polystyrene (PS) blend, PP/PS/polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) ternary blend and their composites with carbon nanofibers (CNF) were investigated. Composites of ternary blend exhibited superior properties compared to those of binary blends. Mechanical performance of nanocomposites was intimately related to their phase morphology. PP/PS/SEBS/0.1 wt% CNF hybrid composites exhibited excellent impact strength (Four-fold increase compared to PP/PS blend) and ductility (12-fold increase in elongation at break, with respect to PP/PS blend). Moreover, these composites displayed good tensile strength and modulus (15% increase in Young's modulus, compared to PP/PS/SEBS blend) and are suitable for various end-use applications including automobile applications. Although crystallinity of PP phase is decreased by the incorporation of CNF, thermal stability of the composites remained almost unaffected. Contact angle measurements revealed that ternary composites exhibited maximum hydrophobicity.