Effect of maleic anhydride treatment on steam and water absorption of wood polymer composites prepared from wheat straw,cane bagasse,and teak wood sawdust using Novolac as matrix

Wheat straw, cane bagasse, and teak sawdust (agrowaste) were sieved up to a 425‐μm mesh size and employed for sheet preparation with and without maleic anhydride (MA) treatment using Novolac resin in a 50 : 50 (w/w) ratio. The shore D hardness of MA treated and untreated wood polymer composites (WPCs) was measured. The MA treated WPCs showed 2–3 times more hardness than that of the untreated respective WPCs. Moisture absorption had a detrimental effect on the mechanical properties of the WPCs. MA treatment restricted swelling and water and steam absorption in the agrowaste. Teak sawdust showed the best results in all respects among the three WPCs. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2963–2967, 2000     

Improving adhesion of wood fiber with polystyrene by the chemical treatment of fiber with a coupling agent and the influence on the mechanical properties of composites

—The mechanical properties of polystyrene filled with chemithermomechanical pulp and wood residues of softwood and hardwood species, which were precoated with phthalic anhydride and various polymers, e.g. polystyrene and PVC, have been investigated. The extent of improvement in the mechanical properties of the composite materials depends on the coating composition, the concentration of phthalic anhydride, the nature of the coated polymers, as well as the concentration of fiber, the nature of the wood species, and the nature of the pulps. Experimental results indicate that phthalic anhydride acts as a coupling agent, but when its performance was compared to that of poly[methylene (polyphenyl isocynate)], it seemed inferior to the latter.     

马来酸酐接枝聚丙烯纤维的结构和性能研究

采用熔融纺丝法制备了马来酸酐(MAH)接枝聚丙烯纤维,考察了接枝纤维的力学性能和吸湿率以及马来酸酐的残留量。结果表明,马来酸酐接枝聚丙烯纤维的断裂强度比纯聚丙烯纤维的低,接枝率越高强度越低,断裂伸长率则相反;随着接枝率的增加,纤维的取向度也逐渐升高。与聚丙烯纤维相比,接枝聚丙烯纤维的吸湿率有了明显提高,在相同拉伸倍数下提高了3-5倍;MAH残留量相当于接枝率(0.73％)的3.7％,表明主要是接枝的马来酸酐改变了聚丙烯纤维的性质。     

木粉疏水改性对HDPE基木塑复合材料性能的影响

采用一种操作简便且易于工业推广的方法对木粉进行疏水改性,具体过程为：将3种可热聚合的单体,即甲基丙烯酸甲酯（MMA）、甲基丙烯酸丁酯（BMA）和苯乙烯（St）均匀喷洒在木粉上,经过预热处理后,与配方中其他组分,如高密度聚乙烯（HDPE）和马来酸酐接枝聚乙烯（MAPE）等通过高速混合机混合均匀,采用双螺杆挤出机造粒后,注射制备木塑复合材料（WPC）样条,测试其力学性能。另外,考察了疏水改性对WPC接触角、维卡软化温度、洛氏硬度、吸水性能、热性能的影响规律。结果表明：疏水改性后WPC的接触角增大,木粉和HDPE的界面相容性改善,力学性能得到明显提高。其中,当MMA、BMA和St的添加量为3%时,WPC的力学性能最好,与疏水改性前相比,弯曲强度分别提高了17.3%、26.3%和27.5%,弯曲模量分别提高了24.4%、24.4%和26.0%,冲击强度分别提高了54.7%、57.7%和60.5%。 此外,疏水改性后WPC的维卡软化温度、洛氏硬度、耐水性和耐热性也得到改善。     

Synthesis of ultrafine poly(styrene‐maleic anhydride) and polystyrene fibers by electrospinning

Fiber formation from atactic polystyrene (aPS) and alternating poly(styrene‐maleic anhydride) (PSMA) synthesized by free radical polymerization (AIBN, 90°C, 4 h) were investigated by electrospinning from various solutions. aPS was soluble in dimethylformamide (DMF), tetrahydrofuran (THF), toluene, styrene, and benzene, whereas PSMA was soluble in acetone, DMF, THF, dimethylsulfoxide (DMSO), ethyl acetate, and methanol. aPS fibers could be electrospun from 15 to 20% DMF and 20% THF solutions, but not from styrene nor toluene. PSMA, on the other hand, could be efficiently electrospun into fibers from DMF and DMSO at 20 and 25%, respectively. Few PSMA fibers were, however, produced from acetone, THF, or ethyl acetate solutions. Results showed that solvent properties and polymer–solvent miscibility strongly influenced the fiber formation from electrospinning. The addition of solvents, such as THF, generally improved the fiber uniformity and reduced fiber sizes for both polymers. The nonsolvents, however, had opposing effects on the two polymers, i.e., significantly reducing PSMA fiber diameters to 200 to 300 nm, creating larger and irregularly shaped aPS fibers. The ability to incorporate the styrene monomer and divinylbenzene crosslinker in aPS fibers as well as to hydrolyze PSMA fibers with diluted NaOH solutions demonstrated potential for post‐electrospinning reactions and modification of these ultrafine fibers for reactive support materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of fiber treatment on the mechanical properties of hybrid fiber reinforced polystyrene composites. Part II. Use of glass fiber and wood pulp as hybrid fiber

The mechanical properties of polystyrene reinforced with a mixture of hardwood aspen chemithermomechanical pulp (CTMP) and surface-treated glass fiber have been studied. The adhesion of cellulose fiber to glass fiber as well as to thermoplastics improved thanks to various surface treatments of CTMP, e.g. coating with polymer+isocyanate or with silane, and grafting with polystyrene. In general, compared with non-treated CTMP-filled composites, the mechanical properties improved when surface-treated wood fiber was used as a filler. Experimental results indicate better compatibility between treated wood fiber and surface-treated glass fiber as well as polystyrene and, consequently, the mechanical properties were enhanced.     

苯乙烯-异戊二烯-苯乙烯嵌段共聚物及其接枝马来酸酐增韧聚苯乙烯/纳米碳酸钙复合材料

以过氧化二异丙苯（DCP）为引发剂,通过单螺杆挤出机熔融挤出,制备了苯乙烯-异戊二烯-苯乙烯接枝马来酸酐（SIS—MAH）,研究了SIS及SIS—MAH对聚苯乙烯（Ps）／纳米碳酸钙（nano—CaCO3）复合材料物理、力学性能的影响,对其结构进行了表征。结果表明,MAH的用量宜为SIS质量分数的3％,DCP的用量应小于MAH质量分数的0．3％;当1份nano—CaCO3加入到PS／SIS（质量比100／2）复合材料3中,SIS与nano—CaCO3产生协同增韧效应,复合材料的无缺口冲击强度可提高到9．83kJ／m^2,但其缺口敏感性增大;SIS—MAH较SIS对PS／nano—CaCO3复合材料具有更好的增韧效果,接枝率为3．08％的SIS—MAH改性PS／CaCO3复合材料（质量比100／5／6）的无缺口冲击强度可提高到11．69kJ／m^2;当SIS用量为6份时,SIS改性复合材料不发生弯曲断裂;当SIS—MAH用量为2份时,SIS—MAH改性复合材料不发生弯曲断裂。     

顺酐化聚苯乙烯对PVC/SEBS共混物的增容作用

以顺酐化聚苯乙烯(PS-g-MAH)为增容剂,研究了苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)对聚氯乙烯(PVC)的共混增韧改性,讨论了该共混物在常温、低温下的力学性能及动态力学性能。结果表明,PS-g-MAH能明显改善SEBS与PVC的相容性,使PVC/SEBS共混物中分散相颗粒尺寸明显减小,分布更均匀,共混物的玻璃化转变温度内移,常温和低温下缺口冲击强度增大。当PVC/PS-g-MAH/SEBS(质量比)为75/6/25时,共混物的常温缺口冲击强度为50.6 kJ/m2,低温(-20℃)缺口冲击强度为29.8 kJ/m2。     

Modification of wood flour/PLA composites by reactive extrusion with maleic anhydride

MA modified wood flour/PLA composites were prepared by one‐step reactive extrusion, in which wood flour and poly(lactic acid) (PLA) were used as raw material, maleic anhydride (MA) was used as modifier, and dicumyl peroxide (DCP) was used as initiator. The influences of MA concentration on the morphology, thermal stability, rheological, and mechanical properties of the composites were studied. The addition of MA improved the compatibility of the composites significantly. The thermal and rheological results showed that with the increase of the concentration of MA, the thermal stability of the composites decreased, the storage modulus and complex viscosity of the composites also decreased. The MA modified composites had an enhanced mechanical strength compared to the unmodified one. As the concentration of the MA increased, the tensile and flexural strength of the composites first increased and then decreased, and reached a maximum when the concentration of MA was 1 wt %. The MA modified composites showed a better water resistance than the unmodified ones. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43295.     

马来酸酐和苯乙烯接枝改性对天然橡胶/聚丙烯共混物物理机械性能的影响

用动态硫化法制备了天然橡胶(NR)/聚丙烯(PP)热塑性弹性体(TPV)。研究了马来酸酐/苯乙烯/过氧化二异丙苯(MAH/St/DCP)多单体熔融接枝交联改性及纳米二氧化硅用量对NR/PP TPV物理机械性能的影响,讨论了NR/PP TPV的重复加工性能。结果表明,当MAH/St/DCP用量为3.750/1.875/0.375质量份、纳米二氧化硅用量为3质量份时,NR/PP TPV的物理机械性能最好,达到了国内外有关通用橡胶/PP TPV的水平,并且具有较好的重复加工性能。     

Soybean and linseed oil‐based composites reinforced with wood flour and wood fibers

Composites consisting of a conjugated linseed or soybean oil‐based thermoset reinforced with wood flour and wood fibers have been prepared by free radical polymerization. The thermoset resin consists of a copolymer of conjugated linseed oil (CLO) or conjugated soybean oil (CSO), n‐butyl methacrylate (BMA), divinylbenzene (DVB), and maleic anhydride (MA). The composites were cured at 180°C and 600 psi and postcured for 2 h at 200°C under atmospheric pressure. The effect of varying filler load, time of cure, filler particle size, origin of the fillers, and resin composition has been assessed by means of tensile tests, DMA, TGA, Soxhlet extraction followed by ¹H‐NMR spectroscopic analysis of the extracts, and DSC. The best processing conditions have been established for the pine wood flour composites. It has been observed that the addition of MA to the resin composition improves the filler‐resin interaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface modification of UHMWPE fibers by means of polyethylene wax grafted maleic anhydride treatment

A novel surface modification method for ultrahigh molecular weight polyethylene (UHMWPE) fibers to improve the adhesion with epoxy matrix was demonstrated. Polyethylene wax grafted maleic anhydride (PEW‐g‐MAH) was deposited on the UHMWPE fibers surface by coating method. The changes of surface chemical composition, crystalline structure, mechanical properties of fiber and composite, wettability, surface topography of fibers and adhesion between fiber and epoxy resin before and after finishing were studied, respectively. The Fourier transform infrared spectroscopy spectra proved that some polar groups (MAH) were introduced onto the fiber surface after finishing. The X‐ray diffraction spectra indicated that crystallinity of the fiber was the same before and after finishing. Tensile testing results showed that mechanical properties of the fiber did not change significantly and the tensile strength of 9 wt % PEW‐g‐MAH treated fiber reinforced composite showed about 10.75% enhancement. The water contact angle of the fibers decreased after finishing. A single‐fiber pull out test was applied to evaluate the adhesion of UHMWPE fibers with the epoxy matrix. After treatment with 9 wt % PEW‐g‐MAH, a pull‐out force of 1.304 MPa which is 53.59% higher than that of pristine UNMWPE fibers was achieved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46555.     

The effect of maleic anhydride modified polypropylene on the mechanical properties of feather fiber,kraft pulp,polypropylene composites

Composites made of feather fiber (Ff), kraft pulp fiber (Pf), polypropylene (PP), and maleic anhydride modified polypropylene (MaPP) were tested in tension and three‐point bend tests. Composite panels were compression molded from multiple plies of nonwoven, fabric‐like prepreg manufactured with wetlay papermaking equipment. Composites containing all four materials were manufactured with MaPP substitutions for PP of 0–10 wt % at 2 wt % increments. The best mechanical properties were observed with a substitution of 8 wt % MaPP. Composites containing either Pf or Ff were manufactured with MaPP substitutions for PP of 0, 4, and 8 wt %; mechanical properties improved with increases in MaPP content. The improvements in mechanical properties were attributed to fiber/matrix interface improvement by the addition of MaPP. Scanning electron microscopy revealed evidence of improved interfacial bonding on the tensile fracture surfaces. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3771–3783, 2004     

Morphology and properties of polystyrene/agave fiber composites and foams

In this work, agave fibers were blended with polystyrene to produce foamed and unfoamed composites. The effect of fiber size and density reduction on the morphological, thermal, mechanical, and rheological properties, as well as crystallinity and water absorption kinetics of the composites was assessed. The results show that Young's modulus and tensile strength increased with increasing fiber content, but decreased with density reduction. Increasing fiber content and decreasing the size of the fibers both increased crystallinity of the composites. Finally, water uptake and diffusion coefficient were found to increase with increasing fiber content for all sizes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

马来酸酐-丙烯酸酯类共聚物作油煤浆燃料稳定剂研究

以马来酸酐与丙烯酸酯的共聚物为稳定剂,当共聚物中,n(马来酸酐):n(丙烯酸丁酯)=1:5,用吡啶中和,稳定剂的添加量为0.4%时,油煤浆(COM)燃料在3个星期后的棒惯时间仍然小于2 s,碳粉的最高质量含量可达59.4%.该稳定剂用量少、原料易得,有较好的应用前景.     

Surface treatment of eucalyptus wood for improved HDPE composites properties

In this study, the effect of Eucalyptus globulus wood (UE) used as a filler (5–20% w/w) on the physical and thermal properties of high-density polyethylene (HDPE) composites was evaluated. To improve the compatibility with HDPE, the wood was modified (TE) using crude glycerol derived from biodiesel production. The addition of 20% (w/w) of UE or TE led to more rigid and durable composite materials compared to neat HDPE (about 50 or 100% increase in tensile strength, respectively). Composites also revealed 55–75°C higher temperatures at maximal degradation rates. The advantageous behavior of TE over UE in composites was attributed to the improvement of surface morphology of modified wood and it is better compatibility with the HDPE as revealed by surface energy analysis. The changes in wetting behavior of HDPE and ensuing HDPE-TE composites (contact angles of ca 72 and 80°, respectively) explain the matrix-filler interactions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48619.     

Esterification effect of maleic anhydride on swelling properties of natural fiber/high density polyethylene composites

The natural fibers (banana, hemp, and sisal) and high density polyethylene were taken for the preparation of natural fiber/polymer composites in different ratios of 40 : 60 and 45 : 55 (w/w). These fibers were esterified with maleic anhydride (MA) and the effect of esterification of MA was studied on swelling properties in terms of absorption of water, at ambient temperature, and steam. It was found that the steam penetrates more within lesserperiod of time than water at ambient temperature. Untreated fiber composites show more absorption of steam and water in comparison to MA‐treated fiber composites. The more absorption of water was found in hemp fiber composites and less in sisal fiber composites. Steam absorption in MA‐treated and untreated fiber composites are higher than the water absorption in respective fiber composites. The natural fiber/polymer composites containing low amount of fibers show less absorption of steam and water at ambient temperature than the composites containing more amount of fibers in respective fiber composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of compatibilizer molecular weight and maleic anhydride content on interfacial adhesion of polypropylene–PA6 bicomponent fibers

The overall goal of the current research was to produce a bicomponent fiber consisting of a isotactic polypropylene sheath and a nylon‐6 core that would be suitable for use in a pigmented carpeting application. To accomplish this, such bicomponent fibers were produced, and in situ reactive compatibilization was achieved using a maleic anhydride–functionalized polypropylene (PP–MA) at the interface. Bicomponent fibers with a side‐by‐side configuration were also spun as part of the investigative process. The adhesion of the materials at the interface and, therefore, the wear characteristics of the fibers were found to depend strongly on the molecular weight and the maleic anhydride content of the functionalized polypropylene. The wear properties and the quality of interfacial adhesion were characterized using optical microscopy to observe fiber cross sections and by accelerated wear testing of carpet samples. Differential scanning calorimetry, capillary rheometry, and tensile testing allowed for additional characterization of the materials in order to explain the differences noted in fiber performance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 130–141, 2001     

Surface modification of nanocrystalline cellulose and its application in natural rubber composites

As a biopolymer with high mechanical strength, nanocellulose was generally considered as a green filler for reinforcing polymer. In this study, nanocrystalline cellulose (NCC) isolated from softwood pulp was successfully modified by cetyltrimethyl ammonium bromide (CTMAB), a cationic surfactant, and the modified nanocrystalline cellulose (m-NCC) was used to reinforce natural rubber (NR). In this composite architecture, it was found that when the filler content was 5 or 10 phr, the surface modification of NCC improved the dispersion state of NCC in NR matrix and the interfacial interaction between NR and NCC. Therefore, the NR/m-NCC composites exhibited outstanding mechanical properties, and its tensile strength, elongation at break and tear strength was increased by 132.8, 20, and 66.1%, respectively, compared to pristine NR composites. Besides, the modified NCC could accelerate the vulcanization and improve wet-skid resistance and aging resistance of NR composites. It is envisioned that the modified NCC has the potential to be generalized to manufacturing other polymer matrix composites strengthened with nanocellulose.     

Thermal and mechanical properties of wood flour–polystyrene blends from postconsumer plastic waste

Polystyrene (PS) from packing materials and plastic cups was reinforced with 30 and 50% wood flour through a blending process with and without a commercial compatibilizing agent. The processability of the pure recycled polystyrene (rPS) and wood–rPS composites was studied in terms of the torque of the mixing process; this was then compared with that of a commercial virgin multipurpose PS. The physical and mechanical properties were compared with those of the virgin PS reinforced with 30 and 50% wood flour. The results show that the mechanical properties of the pure and reinforced rPS did not decrease with respect to the virgin PS, and in terms of the impact strength, the rPS was superior to the virgin plastic. The mechanical properties were not affected by the commercial compatibilizing agent, but the torque of the blends was significantly lower with the compatibilizer. Differential scanning calorimetry (DSC) and dynamic mechanical analysis were used to study the glass‐transition temperature (T_g) of both the pure virgin PS and pure rPS and the wood flour–PS composites. The T_g values of the rPS and wood–rPS composites were higher than those of the virgin PS and wood–virgin PS composites. The use of rPS increased the stiffness and flexural modulus of the composites. Thermogravimetric analysis revealed that the thermal stability of rPS and its composites was slightly greater than that of the virgin PS and its composites. These results suggest that postconsumer PS can be used to obtain composite materials with good mechanical and thermal properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011