PP-g-MA和UP增容PP/玻璃纤维复合材料性能的研究

以聚丙烯-马来酸酐接枝(物PP-g-MA)和不饱和聚(酯UP)作为界面相容剂,研究了界面相容剂对玻璃纤维增强PP复合材料力学性能及界面黏结的影响。结果表明:加入PP-g-MA或UP,玻璃纤维增强PP复合材料的力学性能明显提高,且UP的增容效果优于PP-g-MA。在玻璃纤维含量为40%时,PP/UP/GF复合材料的拉伸强度比未改性的复合材料的拉伸强度提高了150%,弯曲强度提高了132%,冲击强度提高了89%;扫描电镜照片表明:PP-g-MA和UP使被拔出玻璃纤维表面黏附了一层树脂,增强了PP与玻璃纤维之间的界面黏结作用;DSC测试表明:PP-g-MA和UP同时加入使复合材料熔融峰温度下降结,晶度增加。     

滑石、CaCO3、BaSO4填充PP复合材料力学性能及界面相互作用对比

以3种白色矿物粉体［颗粒状CaCO₃、BaSO₄,片层状滑石（talc）］为填料,聚丙烯（PP）为基体树脂,通过熔融共混法制备PP复合材料,研究3种矿物粉体在不同含量时对PP复合材料的力学性能、流动性能与断裂形貌的影响规律,并采用Turcasanyi半经验公式计算了矿物填料与PP复合材料力学性能界面相互作用。结果表明,3种矿物粉体的加入均降低了PP的拉伸强度,PP/talc复合材料的拉伸强度明显高于PP/CaCO₃ 与PP/BaSO₄,且talc的加入明显增强了PP的拉伸模量与弯曲模量;CaCO₃ 与BaSO₄的加入使复合材料弯曲强度降低,talc的加入使复合材料弯曲强度提高;CaCO₃对PP断裂伸长率与悬臂梁缺口冲击强度的提升最为明显;talc的加入使复合材料流动性能得到提高,而颗粒状的CaCO₃与BaSO₄的加入对加工性能影响较小;CaCO₃ 与BaSO₄在PP中均存在一定团聚现象,且与PP相容性较差,存在明显界面缺陷;talc与PP间界面较模糊,二者之间有较强的黏结作用。     

界面强度对玻璃纤维增强不饱和聚酯复合材料静态和动态力学性能影响

采用3种高强高模玻璃纤维与不饱和树脂,分别制备了3种单向板复合材料和3种织物复合材料,通过纤维束拔出法和韦布分析法表征了3种玻璃纤维与不饱和树脂间的界面结合强度,并研究了界面强度与复合材料静态和动态力学性能。结果表明:3种纤维的本征界面强度分别为27.12,34.91,35.60MPa;界面强度对复合材料静态力学与疲劳性能有着重要的影响,但对模量的影响较小。随着界面强度的增加,90°方向的拉伸强度逐渐增加,但是0°方向上的拉伸强度反而下降。当疲劳应变较低时,界面强度的增加有助于疲劳性能的提高;但当疲劳应变提高时,界面强度对疲劳性能的影响降低,与材料初始强度反而有着明显的相关性。     

聚丙烯／木粉复合材料的加工成型及其力学性能研究

采用混炼工艺制备了聚丙烯／木粉复合材料（WPC）。研究了木粉、界面增溶剂-马来酸酐接枝聚丙烯（MAPP）的用量对WPC力学性能的影响。采用红外光谱仪对PP、MAPP、木粉及WPC的结构进行了表征和分析。结果表明，聚丙烯中加入木粉后，复合材料的拉伸强度及弯曲强度均比纯PP的要低，拉伸模量和弯曲模量逐渐升高，但复合材料的拉伸断裂伸长率随木粉用量的增加而逐渐下降。随着MAPP用量的增加，木粉用量较低（10％、20％）的WPC的拉伸强度和弯曲强度均先增加，然后逐渐减少，而木粉用量较高的WPC的强度值却在不断增高。当MAPP的质量分数为2％-4％时，复合材料的冲击强度值一般达到最高。红外谱图研究表明，偶联剂的加入可以把木纤维中的羟基酯化，改善木塑界面之间的相容性。     

增容改性对PP/废PCB粉复合材料力学性能的影响

以废印刷电路板(PCB)粉对聚丙烯(PP)进行填充改性,采用熔融共混法制备了PP基复合材料。通过力学性能测试研究了硅烷偶联剂KH-550、马来酸酐接枝聚丙烯(PP-g-MAH)两种改性剂的引入对PP/废PCB粉复合材料力学性能的影响,并用扫描电镜(SEM)观察了复合材料的冲击断面形貌。结果表明:KH-550和PPg-MAH均能有效改善PP/废PCB粉复合体系的界面黏结效果,二者的最佳用量分别为2%和4%,其中PP-gMAH对复合材料的改性效果优于KH-550。引入了PP-g-MAH的复合材料,其拉伸和弯曲强度最高可比未改性复合材料分别提升52.2%和31.2%,同时材料的冲击强度亦保持了较高值。     

改性剂对连续玻璃纤维增强PP复合材料力学性能的影响

采用熔体挤出浸渍工艺制备连续合股无捻粗玻璃纤维(CUGF)增强聚丙烯(PP)复合材料。研究了以硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH550)和PP接枝马来酸酐(PP-g-MAH)为界面改性剂对CUGF填充PP复合材料的界面相容性和PP力学性能的影响。结果表明,PP/PP-g-MAH/CUGF复合材料的力学性能明显优于PP/KH550/CUGF复合材料。在CUGF的质量分数为27%时,PP/PP-g-MAH/CUGF复合体系的拉伸强度比PP/KH550/CUGF复合体系的拉伸强度提高了47%,弯曲强度提高了64%,冲击强度提高了30%;黏弹行为显示,PP/PP-g-MAH/CUGF复合体系的弹性模量和黏性模量始终处于高位,说明分子链之间的相互作用增强,链段运动受到限制,PP分子链松弛时间增加;扫描电子显微镜照片显示,PP-g-MAH改善了PP树脂与玻璃纤维间的相容性,提高了界面黏结强度,使得拔出的CUGF表面黏附了一层树脂。     

PP/核桃壳粉复合材料的制备与性能研究

以核桃壳粉(WSP)为填料,采用熔融共混法制备了聚丙烯(PP)/WSP复合材料。研究了聚丙烯接枝马来酸酐(PP-g-MAH)界面相容剂、三元乙丙橡胶(EPDM)弹性体等对PP/WSP复合材料力学性能和热稳定性的影响。结果表明:PP-g-MAH界面相容剂能够改善WSP与PP的界面相容性,增强界面黏结强度,提高复合材料的力学性能,添加7%的PP-g-MAH可以使WSP用量为50%的PP/WSP复合材料的拉伸强度提高49.5%,弯曲强度提高52.9%;而添加EPDM弹性体的PP/WSP复合材料的韧性显著改善。WSP对聚合物基体的热稳定性有一定促进作用。     

两种无机粒子填充聚合物复合材料界面黏结强度表征参数对比研究

界面黏结强度是影响无机粒子填充热塑性塑料力学性能的重要因素之一。引入界面相互作用参数和界面脱黏角两种无机粒子填充聚合物复合材料界面黏结强度参数,并以无机粒子填充聚丙烯复合材料为例,表征了无机粒子与聚合物界面的黏结强度,考察了两者之间的相关关系。结果表明,两种界面黏结强度表征参数呈明显线性负相关关系。     

硬质无机粒子填充聚丙烯基复合材料的增韧机理及其定量判据

综述了硬质无机粒子(RIP)填充聚丙烯(PP)复合材料的増韧机理及其定量判据。大量的研究表明,最典型的增韧机理有逾渗模型理论、银纹化微观增韧机理和柔性界面层理论。在定量分析RIP填充PP复合材料的增强机理方面,主要阐述了两种判据:基体层厚度判据和界面黏结强度判据;并利用所述判据分析了相关文献的数据,得出了如下结论:当RIP平均粒径d临界粒径dc,体积分数Φf临界体积分数Φf C,或平均基体层厚度L临界基体层厚度Lc;界面相互作用参数B值在[1,2.6]之间时,RIP增强填充PP复合材料的韧性的机会较大。     

松木纤维表面超支化接枝改性及其对PP复合材料性能的影响

为了改善松木纤维与聚丙烯(PP)之间的界面结合性能,采用接枝改性技术在纤维表面逐步接枝超支化聚酰胺,并用接枝改性后的纤维与PP及相容剂熔融共混制备复合材料。采用傅里叶变换红外光谱及热重分析对改性前后纤维的官能团及热性能进行了分析表征,并对纤维增强PP复合材料的拉伸强度进行了测定。结果表明,经超支化聚酰胺改性后,纤维表面成功引入了大量的氨基基团。经1.0代超支化聚酰胺接枝改性后,纤维的耐热性有所增加,但经2.0及3.0代超支化聚酰胺接枝改性后,纤维的耐热性均有所下降。经超支化聚酰胺接枝改性后,纤维增强PP复合材料的拉伸强度均有所提高,其中2.0代超支化聚酰胺改性的纤维增强PP复合材料拉伸强度最高。对于未改性或KH–550改性的纤维,其目数为20目时的复合材料拉伸强度较目数为40目的高,但超支化聚酰胺接枝改性的纤维增强复合材料拉伸强度随纤维尺寸的变化情况与此相反。     

Quantitative description of interfacial strength in polypropylene/inorganic particle composites

The parameters characterizing the interfacial adhesion strength, such as interaction parameter (B) and interfacial adhesion angle (θ), of inorganic particulate‐filled polymer composites were analyzed in this paper. On the basis of the previous studies and the research work reported in literature, several expressions for predicting these parameters and the determination methods of these parameters were proposed, and the relationship between the interaction parameter and interfacial adhesion angle was discussed. Then the parameters B and θ were estimated from the experimental measured tensile strength of the several inorganic particulate‐filled polypropylene (PP) composites including nanometer calcium carbonate, glass bead and diatomite particles. The results showed that the value of θ was about from 44 to 75 degrees while the value of B was varying from 1.12 to 2.42 of these filled systems under the experimental conditions. Moreover, the value of B decreased roughly linearly with increasing θ for these particulate‐filled PP composites.POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Crystallization behaviors and foaming properties of diatomite-filled polypropylene composites

The non-isothermal crystallization kinetics and foaming properties of polypropylene (PP) filled with various contents of diatomite were investigated. The results showed that the diatomite had strong effects on the PP crystallization kinetics, which significantly increased the crystallization temperature and reduced crystallite size. These were attributed to the nucleation effect of the diatomite particles and the complex interface properties between the PP chains and diatomite particles. Non-isothermal crystallization can be well described by the Mo’s method. The non-isothermal crystallization activation energy calculated by the Kissinger’s method increased with increased content of diatomite. The foamed PP composites, in particular, the PP composites filled with 10 wt% diatomite had better cell morphology ascribed to the facilitated crystallization and increased polymer melt strength compared with the foamed pure PP.     

Morphological,mechanical, and physical properties of composites made with wood flour‐reinforced polypropylene/recycled poly(ethylene terephthalate) blends

Wood flour (WF)‐filled composites based on a polypropylene (PP)/recycled polyethylene terephthalate (r‐PET) matrix were prepared using two‐step extrusion. Maleic anhydride grafted polypropylene (MAPP) was added to improve the compatibility between polymer matrices and WF. The effects of filler and MAPP compatibilization on the water absorption, mechanical properties, and morphological features of PP/r‐PET/WF composites were investigated. The addition of MAPP significantly improved mechanical properties such as tensile strength, flexural strength, tensile modulus, and flexural modulus compared with uncompatibilized composites, but decreased elongation at break. Scanning electron microscopic images of fracture surface specimens revealed better interfacial interaction between WF and polymer matrix for MAPP‐compatibilized PP/r‐PET/WF composites. MAPP‐compatibilized PP/r‐PET/WF composites also showed reduced water absorption due to improved interfacial bonding, which limited the amount of absorbable water molecules. These results indicated that MAPP acts as an effective compatibilizer in PP/r‐PET/WF composites. POLYM. COMPOS., 38:1749–1755, 2017. © 2015 Society of Plastics Engineers     

The preparation and tensile properties of polyethylene composites

Single polymer composites have been prepared using different morphologies of polyethylene as matrix and as the reinforcement. Depending on annealing conditions, the ultraoriented fibers used as reinforcement can have higher melting points (ca. 139°C) than the matrix made from the same conventionally crystallized high-density polyethylene (ca. 132°C) or from low-density polyethylene (ca. 110°C). The optimum temperature has been assessed for bonding to occur by growth of transcrystalline regions from the melt matrix without considerable modulus reduction of the annealed ultraoriented and reinforcement fiber or film. Pullout tests have been used for determining the interfacial shear strength of these single polymer composites. The interfacial shear strength for the high-density polyethylene films embedded in a low-density polyethylene matrix is 7.5 MPa and for high-density polyethylene self-composites is 17 MPa. These values are greater than the strength for glass-reinforced resins. The strength is mainly due to the unique epitaxial bonding which gives greater adhesion than the compressive and radial stresses arising from the differential shrinkage of matrix and reinforcement. The tensile modulus of composites prepared from uniaxial and continuous high-density polyethylene films embedded in low-density polyethylene obeys the simple law of mixtures and the reinforced low-density polyethylene modulus is increased by a factor of 10. High strength cross-ply high-density-polyethylene—low-density-polyethylene laminates have also been prepared and the mechanical properties have been studied as the film orientation is varied with respect to the tensile axis.     

Effect of fiber pretreatment condition on the interfacial strength and mechanical properties of wood fiber/PP composites

The effect of fiber surface pretreatment on the interfacial strength and mechanical properties of wood fiber/polypropylene (WF/PP) composites are investigated. The results demonstrate that fiber surface conditions significantly influence the fiber–matrix interfacial bond, which, in turn, determines the mechanical properties of the composites. The WF/PP composite containing fibers pretreated with an acid–silane aqueous solution exhibits the highest tensile properties among the materials studied. This observation is a direct result of the strong interfacial bond caused by the acid/water condition used in the fiber pretreatment. Evidence from coupling chemistry, rheological and electron microscopic studies support the above conclusion. When SEBS‐g‐MA copolymer is used, a synergistic toughening effect between the wood fiber and the copolymer is observed. The V‐notch Charpy impact strength of the WF/PP/SEBS‐g‐MA composite is substantially higher than that of the WF/PP composite. The synergistic toughening mechanisms are discussed with respect to the interfacial bond strength, fiber‐matrix debonding, and matrix plastic deformation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1000–1010, 2000     

Physical and Mechanical Properties of Polypropylene Reinforced with Fe Particles

ABSTRACT

The physical and mechanical properties of Polypropylene (PP) and Fe-PP polymer composites containing 5, 10, and 15 vol% Fe were investigated experimentally. After preparing PP and Fe–PP polymer composites with a twin screw extruder and injection molding, the following properties were determined: yield and tensile strength, the modulus of elasticity, % elongation, hardness (Shore D), Izod impact strength (notched), melt flow index (MFI), Vicat softening point, Heat deflection temperature (HDT), and melting temperature (Tm) of PP and metal-polymer composites. As compared to PP, It was found that by increasing the vol% of Fe in PP, notched Izod impact strength, yield and tensile strength, and % elongation decreased. On the other hand, the modulus of elasticity, hardness, MFI, vicat softening point, and HDT values increased with the amount of iron.     

Physical properties of polypropylene composites with hydrophobized cellulose powder by soybean oil

Cellulose materials have attracted lots of interest as potential natural fillers in the production of green polymer composites because they are ecofriendly and economic. In this study, to improve the interfacial bonding strength between cellulose powder and a hydrophobic polypropylene (PP) matrix, the surface hydrophobization of cellulose powder by soybean oil was carried out via a simple transesterification reaction procedure. Weight change measurements, Fourier transform infrared spectroscopy, and compatibility testing were used to quantitatively and qualitatively analyze the hydrophobization of the cellulose powder. By changing the hydrophobization conditions, the soybean oil content attached to the cellulose powder changed from 8.0 to 57.8%. PP composites with 20% of each hydrophobized cellulose powder were prepared by melt blending followed by compression molding. The mechanical properties of the PP composites were investigated with a universal testing machine and an Izod impact tester. Compared to the composite with pristine cellulose powder, the PP composite with the hydrophobized cellulose powder and an attached soybean oil content of 29.6% showed largely increased impact strength (46.3%), tensile strength (47.5%), and elongation at break (27.3%) values. The scanning electron microscopy images for the fracture surfaces of the composites showed that the hydrophobization induced much stronger interfacial bonding between the PP matrix and cellulose powder. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42929.     

PP/硅藻土复合材料拉伸性能的研究

考察了硅藻土粒径和含量对填充聚丙烯复合材料的拉伸性能的影响。结果表明,当硅藻土体积分数时,复合材料的拉伸强度和断裂强度都有所下降,然后,两者均有轻微的提高;除个别测量点外,复合材料的断裂伸长率随着的增加而明显增大;当时,硅藻土粒径为7μm的填充体系的拉伸强度和拉伸断裂强度最高。     

Pineapple leaf fiber reinforced thermoplastic composites: Effects of fiber length and fiber content on their characteristics

Pineapple leaf fiber (PALF) was used as a reinforcement in polyolefins. Polypropylene (PP) and low‐density polyethylene (LDPE) composites with different fiber lengths (long and short fibers) and fiber contents (0–25%) were prepared and characterized. The results showed that the tensile strength of the composites increased when the PALF contents were increased. It was observed that the composites containing long fiber PALF were stronger than the short fiber composites as determined by greater tensile strength. An SEM study on the tensile fractured surface confirmed the homogeneous dispersion of the long fibers in the polymer matrixes better than dispersion of the short fibers. The unidirectional arrangement of the long fibers provided good interfacial bonding between the PALF and polymer which was a crucial factor in achieving high strength composites. Reduction in crystallinity of the composites, as evident from XRD and DSC studies suggested that the reinforcing effect of PALF played an important role in enhancing their mechanical strength. From the rule of mixtures, the stress efficiency factors of the composite strength could be calculated. The stress efficiency factors of LDPE were greater than those of PP. This would possibly explain why the high modulus fiber (PALF) had better load transfers to the ductile matrix of LDPE than the brittle matrix of PP. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Isolation and characterization of betel nut leaf fiber: Its potential application in making composites

Betel nut leaf fiber (BNLF) is a new finding as cellulosic filler for polymer composites. Its main constituents are 75% α‐cellulose, 12% hemicelluloses, 10% lignin, and 3% others matter, viscosity average molecular weight 132,000 and degree of crystallinity 70%. In the present work, BNLF reinforced polypropylene (PP) composites were prepared using heat press molding method. 5–20 wt% short length fiber is taken for getting benefits of easy manufacturing and the fiber was chemically treated with NaOH, dicumyl peroxide (DCP), and maleic anhydride‐modified PP (MAPP) to promote the interfacial bond with PP. The extent of modification of fiber was assessed on the basis of morphology, bulk density, moisture absorption, thermal, and mechanical properties of untreated fiber, treated fiber, and their reinforcing PP composites. The tensile and flexural strength of composites increase with the increase of fiber loading up to 10 and 20 wt%, respectively. It was also observed that Young's modulus and flexural modulus increase with fiber loading. The thermal degradation behavior of resulting composites was investigated. Among the various treated fibers, MAPP‐treated fiber composite showed best interfacial interactions as well as mechanical and thermal properties. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers