Performance evaluation of synthesized acrylic acid grafted polyethylene in aluminum hydroxide highly filled polyethylene composites

A polymeric agent acrylic acid grafted polyethylene (AAgPE) was synthesized and used as a coupling agent in aluminum hydroxide [Al(OH)₃] highly filled linear low‐density polyethylene (LLDPE) composite. It is found that AAgPE improves the interfacial adhesion between the filler and the polyethylene matrix, which results in good mechanical properties of the composite. Silicon oil is an effective additive for improving the impact strength, the elongation at break, and the rheological property of the filled composite, but it decreases the tensile strength remarkably. The combination of AAgPE and silicon oil can lead to good performance of the composite. Flammability properties and fracture surface morphologies of the composites through scanning electron microscopy were investigated. The relationship between mechanical properties and microstructure of the composites was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2544–2549, 2002     

Reinforcing performance of recycled PET microfibrils in comparison with liquid crystalline polymer for polypropylene based composite fibers

Recycled polyethylene terephthalate (rPET) used as an alternative reinforcing additive for polypropylene (PP) based composite fibers, compared with liquid crystalline polymer (LCP), was investigated. Both PP-LCP and PP-rPET composites were prepared as fiber using hot drawing process. The effects of draw ratios and compatibilizer dosages on morphology in relation to tensile properties of both types of the composite systems were studied. The variation of draw ratios resulted in much change of stress–strain behavior in compatibilized rPET composite system owing to the obvious difference in morphological change of rPET dispersed phase upon drawing. Tensile strength and extensibility of both composites system were significantly improved with compatibilizer loading. The tensile strength of compatibilized rPET-composite fibers was higher than that of the compatibilized LCP system. The obtained results demonstrated the high potential of rPET as a well-defined reinforcing material for PP based composite fiber under the improved interfacial adhesion promoted by compatibilizer.     

The use of a modified microindentation technique to evaluate enviro-mechanical changes in composite interphase properties

Fiber sizing can improve the performance of fiber-reinforced polymer composites. The focus of this work was to determine if the improvement in performance could be ascertained from a micromechanical test for interfacial adhesion on as-processed materials under hygrothermal exposure. Three types of sizings were examined: a carboxyl modified poly(hydroxyether), that is identified as low spread phenoxy (LSP), a poly(vinylpyrrolidone) (PVP) sample and a standard industrial sizing (G′). A nanoindenter was effectively used to obtain interfacial shear strength (IFSS) using a modified micro-indentation technique. The results showed that LSP outperforms the PVP and G′ materials in bulk composite properties, but showed equivalent interfacial shear strength to G′ and experienced hygrothermal degradation in interfacial adhesion that the PVP did not. The LSP composite loses 10% of its original interfacial shear strength after 576 h, while for PVP composite it improves by 25%. The tensile strengths for LSP and PVP composites decrease by 7% and 10%, respectively, at 576 h of hygrothermal exposure. The relationship between tensile strength and interfacial adhesion proved to be weak, but processing defects and other failure processes showed a strong influence of interfacial adhesion on tensile strength of compsites.     

Effect of filler loading and coconut oil coupling agent on properties of low‐density polyethylene and palm kernel shell eco‐composites

Palm kernel shell (PKS), a waste from the oil palm industry, has been utilized as filler in low‐density polyethylene (LDPE) eco‐composites in the present work. The effect of PKS content and coconut oil coupling agent (COCA) on tensile properties, water absorption, and morphological and thermal properties of LDPE/PKS eco‐composites was investigated. The results show the increase of PKS content decreased the tensile strength and elongation at break, but increased the tensile modulus, crystallinity, and water absorption of eco‐composites. The presence of COCA as coupling agent improved the filler‐matrix adhesion yield to increase the tensile strength, tensile modulus, crystallinity, and reduced water absorption of eco‐composites. The better interfacial adhesion between PKS and LDPE with the addition of COCA was also evidenced by scanning electron microscopy studies. J. VINYL ADDIT. TECHNOL., 22:200–205, 2016. © 2014 Society of Plastics Engineers     

Chemical Modification of Chitosan-Filled Polypropylene (PP) Composites: The Effect of 3-Aminopropyltriethoxysilane on Mechanical and Thermal Properties

Chitosan was used as filler in polypropylene (PP) polymer. In order to improve compatibility between chitosan and PP, chitosan was chemically modified with 3-aminopropyltriethoxysilane (3-APE). The results show that the increasing of filler content decreased tensile strength and elongation at break, but increased Young's modulus of composites. The treated composites exhibit higher tensile strength and Young's modulus, but lower elongation at break compared untreated composites. The addition of 3-APE has improved thermal properties such as thermal stability and crystallinity of treated composites. SEM study of the tensile fracture surface of treated composites shows better interfacial interaction and adhesion between the chitosan-PP matrix.     

Mechanical properties of surface‐modified ultra‐high molecular weight polyethylene fiber reinforced natural rubber composites

The mechanical properties of ultra‐high molecular weight polyethylene (UHMWPE) fibers reinforced natural rubber (NR) composites were determined, and the effects of fiber surface treatment and fiber mass fraction on the mechanical properties of the composites were investigated. Chromic acid was used to modify the UHMWPE fibers, and the results showed that the surface roughness and the oxygen‐containing groups on the surface of the fibers could be effectively increased. The NR matrix composites were prepared with as‐received and chromic acid treated UHMWPE fibers added 0–6 wt%. The treated UHMWPE fibers increased the elongation at break, tear strength, and hardness of the NR composites, especially the tensile stress at a given elongation, but reduced the tensile strength. The elongation at break increased markedly with increasing fiber mass fraction, attained maximum values at 3.0 wt%, and then decreased. The tear strength and hardness exhibited continuous increase with increasing the fiber content. Several microfibrillations between the fiber and NR matrix were observed from SEM images of the fractured surfaces of the treated UHMWPE fibers/NR composites, which meant that the interfacial adhesion strength was improved. POLYM. COMPOS., 38:1215–1220, 2017. © 2015 Society of Plastics Engineers     

Mechanical and thermal properties of starch‐filled poly(D,L‐lactic acid)/poly(hydroxy ester ether) biodegradable blends

The mechanical, structural, and thermal properties of injection‐molded composites of granular cornstarch, poly(D ,L ‐lactic acid) (PDLLA), and poly(hydroxy ester ether) (PHEE) were investigated. These composites had high tensile strengths, ranging from 17 to 66 MPa, at starch loadings of 0–70 wt %. Scanning electron microscopy micrographs of fracture specimens revealed good adhesion between the starch granule and the polymer matrix, as evidenced by broken starch granules. The adhesion of the starch granules to the polymer matrix was the greatest when the matrix PDLLA/PHEE ratios ranged from zero to unity. At a PDLLA/PHEE ratio of less than unity, as the starch content increased in the composites, there was an increase in the tensile strength and modulus, with a concurrent decrease in elongation. The effects of starch on the mechanical properties of starch/PDLLA composites showed that as the starch content of the composite increased, the tensile strength and elongation to break decreased, whereas Young's modulus increased. In contrast, the tensile strength of starch/PHEE composites increased with increasing starch content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1775–1786, 2003     

Enhanced adhesion force based on microphase separation induced by complexation of ferric ions and polyurethane matrix

Waterborne polyurethane elastomer (WPU) has been widely used as a glue, but it still has some drawbacks, including a long cure time and weak adhesive force. In order to overcome these drawbacks, a new composite [PU/ferric ion complexation (Fe/PU)] with high adhesive strength was successfully prepared using ferric ion (Fe³⁺) as a complexing agent. Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, and tensile testing were used to characterize the chemical structure and mechanical properties of the as‐obtained composites. Introduction of the ferric ion induces a certain degree of microphase separation, resulting in better mechanical strength and interfacial adhesion. The mechanical properties of the PU composite with ferric ions are higher than that of pure PU. The adhesive strength of the 25%‐Fe/PU composite is 32.46 ± 3.1 MPa, exhibiting superior adhesive strength. The tensile strength was enhanced 34%, and the elongation was enhanced 23.6% compared to pure PU. Furthermore, the Fe/PU composite, coordinated with ferric ions, exhibits an enhanced storage modulus and reduced loss coefficient compared to PU. We can foresee that Fe/PU composites will play an important role in the building and engineering areas. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46069.     

聚乙二醇对聚乳酸/淀粉纳米晶复合材料性能的影响

以聚乳酸（PLA）和淀粉纳米晶（SNC）为主要原料,聚乙二醇（PEG）为增塑剂,采用溶剂蒸发法制备PLA/SNC和PLA/SNC/PEG复合材料,通过差示扫描量热仪（DSC）、热台偏光显微镜（PLM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）等研究了PEG对复合材料结晶行为、力学性能及界面相容性的影响。结果表明,PEG能够与SNC协同促进PLA结晶,使PLA/SNC/PEG复合材料的结晶速率明显提高;PEG的添加未改变PLA/SNC复合材料的结晶结构;随着PEG含量的增加,PLA/4%（质量分数,下同）SNC复合材料的拉伸强度先升高后下降,断裂伸长率不断提高;当PEG含量为2%时,PLA/4%SNC/2%PEG复合材料的力学性能最佳,拉伸强度为47.86 MPa,断裂伸长率为10.20%,PLA与SNC间界面相容性得到改善。     

Study on mechanical properties of perlite‐filled gamma‐irradiated polypropylene

This study covers the preparation and characterization of perlite‐filled polypropylene (PP). The compositions of 15, 30, and 50 % by weight perlite–PP composites were prepared by melt‐mixing. The PP used in this study was either applied in the virgin form or γ‐irradiated in air at the doses of 10, 25, 50, and 100 kGy to determine the effect of oxidative degradation in composite properties. Furthermore, the active sites containing oxygen produced by γ‐irradiation in PP may provide a possible enhancement by the interfacial interaction between perlite and PP. An initial sharp drop in torque readings during the melt‐mixing of perlite–PP composite preparation indicated an extensive chain scission and degradation by γ‐irradiation. The thermal properties of the composites were characterized by DSC. The ultimate tensile strength and elongation and also impact strength decreased in all composites with γ‐irradiation. Yet, these changes appeared not to be faster than was the change in unfilled PP upon irradiation. Scanning electron microscopy revealed an interfacial adhesion between perlite and irradiated PP while virgin PP did not show any evidence of adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2670–2678, 2001     

木质填料种类及含量对木塑复合材料性能的影响

研究了木质填料的种类和含量对木塑复合材料性能的影响。实验发现:随着木粉、竹粉含量的提高,复合材料的拉伸强度、维卡软化温度、弯曲强度和弯曲模量都得到了较大幅度的提高,冲击强度、断裂伸长率和熔体流动速率有所下降。不同粒径和不同种类的木质填料对复合材料的力学性能也有明显的影响,以100目木粉制得复合材料的性能最好,DSC实验数据分析表明:木粉、竹粉含量的变化对复合材料体系的熔融温度有影响;SEM扫描冲击断口形貌表明:相容剂能够有效改善木粉与HDPE界面的相容性,提高界面黏合力,从而使复合材料的性能得到提高。     

挤出-注塑制备黄麻增强PLA复合材料及其性能

通过挤出共混、造粒、注射成型的方式制备了黄麻纤维填充聚乳酸(PLA)复合材料,研究了复合材料的力学性能以及黄麻与PLA之间的微观界面形貌。结果表明:黄麻的加入,并没有很好地改善黄麻/PLA复合材料的拉伸强度和弯曲强度;碱处理后的黄麻与PLA之间的界面性能有所改善;碱处理黄麻的加入,改善了黄麻/PLA复合材料的断裂伸长率与冲击韧性。     

Preparation and mechanical properties of composite of fibrous cellulose and maleated polyethylene

Fibrous cellulose and maleated polyethylene (FC–MPE) composites were prepared under melt mixing by maleation of polyethylene (PE) to obtain maleic anhydride (MA) grafted PE (MPE) and successive compounding of the resultant MPE with fibrous cellulose (FC). When increasing the content of added MA to 2 wt %, the grafting efficiency of MA decreases gradually to 84% and the grafted MA chains become longer. Scanning electron microscopy (SEM) reveals strong adhesion of MPE to FC in the FC–MPE composite, which is probably due to the increased compatibility between MPE and FC, in contrast to no adhesion of unmaleated PE (UPE) to FC in the FC–UPE composite. This difference in interfacial structure between the FC–MPE and FC–UPE composites results in quite different mechanical properties for them. With an increase in the FC content to 60 wt %, the tensile strength of the FC–MPE composite increases significantly and reaches 125% that of pure PE. Furthermore, the larger Young's modulus, larger bending elastic modulus, and smaller elongation of the FC–MPE composite strongly indicate effective transfer of the high tensile strength and elasticity of FC to the MPE matrix through the strong adhesion between FC and MPE. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1971–1980, 2002; DOI 10.1002/app.10428     

Effect of CNT-coated carbon fibres in HDPE composites

The mechanical properties of thermoplastic HDPE composites filled with CF and CNT were studied. Coupling agent surface-treated CF-filled HDPE composites increased their tensile strength and impact strength, which is further increased with the addition of CNT. Coupling agent was proved to play an important role in the improvement of the interfacial adhesion of the CF/HDPE composite. SEM showed that CNT coating-treated CF/HDPE composites show better dispersion of the ?ller into the matrix.     

界面改性对高填充Mg(OH)2/EVA复合材料结构与性能的影响

研究了表面改性剂和界面相容剂对氢氧化镁[Mg(OH)2]在聚乙烯／醋酸乙烯酯(EVA)基体中的分散性、Mg(OH)2与聚合物的界面以及复合材料性能的影响，通过SEM观察了复合材料拉伸断面和切断断面的形貌。结果表明：不同类型的表面改性剂都能不同程度地改善Mg(OH)2的分散性。钛酸酯与其它改性剂相比。又大大加强了Mg(OH)2与基体的界面作用，复合材料表现出较高的拉伸强度和伸长率。但体系的粘度上升；硬脂酸却弱化了界面作用。复合材料的强度下降,伸长率上升，粘度下降。EVA-g-MAH作为界面相容剂能够强化界面作用。提高复合材料的综合性能。水平燃烧结果表明,Mg(OH)2在EVA中分散度提高后。阻燃性能得到了一定程度的提高,当使用具有明显界面作用强化的处理剂时，阻燃性能改善最大。     

Effect of moisture content on mechanical properties,thermal and structural stability and extrudate texture of poly(vinyl chloride)/wood sawdust composites

Mechanical properties and thermal and structural changes of poly(vinyl chloride) (PVC)/wood sawdust composites were assessed with respect to the effect of moisture content, varying from 0.33 to 3.00 % by weight in the composite, for three different wood sawdust contents. The swell ratio and texture characteristics of the composite extrudates were also evaluated. Unique explanations were given to describe changes in the composite properties in terms of molecular interactions between PVC, cellulosic sawdust and moisture, such as dipole–dipole interactions, interfacial defects and bonding, fibre swelling, and moisture evaporation. The results suggest that at low moisture content the tensile modulus decreased and elongation at break of the composites increased with moisture content, the effect being reversed for high moisture content. Tensile strength decreased with increasing moisture content up to 1–2 %, and then unexpectedly increased at higher moisture contents. The effect of moisture content on flexural properties of the composite was similar to that on tensile properties. Impact strength of the composites was considerably improved with moisture content at low sawdust contents (16.7 wt%), and was independent of the moisture content at higher sawdust contents (28.6 and 37.5 wt%). A decrease in decomposition temperature with an increase in polyene content was evidenced with increasing moisture content, while the glass transition temperature did not change with varying moisture content. The extrudate swell ratio increased with the shear rate but remained unaffected by moisture content. The bubbling and peeling‐off in the composite extrudate occurred as a result of the evaporation of water molecules and the application of a high shear rate. Copyright © 2004 Society of Chemical Industry     

Study on Mechanical and Dielectric Properties of Jute Fiber Reinforced Low-Density Polyethylene (LDPE) Composites

Abstract

Jute fiber (Hessian cloth) reinforced low-density polyethylene (LDPE) composites were prepared by heat press molding techniques. The mechanical properties such as tensile strength (TS), bending strength (BS), and elongation at break of the composites were studied. The enhancement of TS (33%) and BS (50%) were obtained as a result of reinforcment jute fabrics in LDPE. In order to improve the mechanical properties and adhesion between jute and LDPE, hessian cloth were each treated with 2-hydroxyl ethyl methacrylate (HEMA). The HEMA-treated jute composite showed higher tensile and bending strength compared to untreated jute composite and LDPE. Dielectric properties like dielectric constant and loss tangent (tan δ) of jute, LDPE and composites were studied. Ferro to paraelectric phase transition occurred in both treated and untreated jute composites containing more than 20% jute. Water uptake behaviors of the composite were monitored and HEMA-treated composite showed lower water absorption behavior. The adhesion nature of jute and LDPE also characterized by scanning electronic microscopy (SEM), better adhesion was observed between HEMA-treated jute and LDPE over untreated ones.     

Mechanical properties of HDPE/bark flour composites

Tensile and impact properties of Neem bark flour (BF) containing high density polyethylene (HDPE) composites were studied at 0–0.26 volume fraction of filler. Tensile modulus and strength and breaking elongation decreased with increase in BF concentration. The decrease in tensile modulus and strength was attributed to the decrease in crystallinity of the polymer compared to the imposed mechanical restraint by the BF. Analysis of tensile strength data indicated formation of stress concentration in the interphase. Because of this stress concentration and the mechanical restraint, the elongation‐at‐break and Izod impact strength decreased. Use of a coupling agent, HDPE‐g‐MAH, brings about enhanced phase adhesion, increasing the tensile modulus and strength. Enhanced adhesion marginally lowers composite ductility at higher filler contents and aids stress transfer increasing the Izod impact strength inappreciably. Scanning electron microscopic studies indicated better dispersion of BF particles and enhanced interphase adhesion in presence of the coupling agent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Recycling carbon fiber from composite waste and its reinforcing effect on polyvinylidene fluoride composite: Mechanical,morphology, and interface properties

Recycled carbon fiber (RCF) was reclaimed from thermoset composite waste and employed as reinforcement from 0 to 30 wt% to prepare polyvinylidene fluoride (PVDF)/RCF composite. Commercial virgin carbon fiber (VCF) was used as comparison. The surface morphology, chemistry, and tensile properties of carbon fibers were investigated by Scanning Electron Microscopy (SEM), X‐Ray Photoelectron Spectroscopy (XPS), and tensile test. Results showed that the roughness, O/C ratio and –COO content of RCF surface were significantly improved after recycling. In addition, the single fiber tensile strength and modulus of RCF was lower than that of VCF. The interfacial adhesion between RCF and PVDF was much stronger due to the high chemical activity and roughness over the RCF surface. Mechanical properties of composites were investigated by flexural test, impact test, and Dynamic Mechanical Analysis (DMA). It is found that the PVDF/RCF composite showed higher flexural properties, storage modulus, and lower impact strength, which indicated the strong interfacial adhesion, played an important role in reinforcing. The morphology of fracture further demonstrated the strong interface in PVDF/RCF composite. The fiber length distribution and crystallinity of composites were also evaluated to characterize the composites. The work develops potential for recycling and reuse of carbon fiber, and also expands the application of PVDF based composite. POLYM. COMPOS., 38:2544–2552, 2017. © 2015 Society of Plastics Engineers     

Mechanical Properties of Benzoylated Oil Palm Empty Fruit Bunch Short Fiber Reinforced Poly(vinyl chloride) Composites

The influence of untreated and benzoylated oil palm empty fruit bunch (OPEFB) short fiber loading on the mechanical properties of the poly(vinyl chloride) (PVC) composite was studied. Benzoylated OPEFB was produced by mixing OPEFB with NaOH solution and agitating vigorously with benzoyl chloride. The PVC resin, various additives, and OPEFB were first dry blended using a laboratory mixer before being milled into sheets on a two-roll mill at 165°C and then hot pressed into composite samples at 180°C. The tensile and impact strength of untreated and benzoylated OPEFB composites decreased whereas the tensile modulus increased with increasing fiber loading from 0 to 40 phr. However, the benzoylated OPEFB was able to improve the tensile properties and impact strength of composites when compared to the untreated fiber. The enhancement of mechanical properties showed that the treatment improved the OPEFB fiber-PVC matrix interfacial adhesion. The improvement of adhesion was clarified by SEM micrographs, the increase of water resistance, and the reduction of glass transition temperature of the composites.