Studies on water absorption of bamboo‐epoxy composites: Effect of silane treatment of mercerized bamboo

The effect of silane treatment on the water absorption properties of bamboo matting reinforced epoxy composites were investigated. Experiments using γ‐aminopropyltriethoxy silane, 3‐trimethoxysilylpropylmethacrylate, vinyltris(2‐methoxyethoxy)silane, bis[3‐(triethoxysilyl)propyl]tetrasulfide, 3‐aminopropyltrimethoxysilane, and n‐octyltrimethoxysilane were carried out to improve the water resistant property of the bamboo fiber composites. Water absorption in the composites was studied by long term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 41 to 26%. Further reduction is observed with silane treatment. Water absorption varies between 21 and 24%, minimum being for aminopropyltriethoxysilane treated composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical and morphological properties of recycled high‐density polyethylene,filled with calcium carbonate and fly ash

In this study, mechanical and morphological properties of composites made up of recycled high‐density polyethylene (HDPE) filled with calcium carbonate and fly ash (FA) were studied. Interfacial interactions were modified to improve the filler compatibility and mechanical properties of the composites by surface treatment of the FA filler with 3‐amino propyl triethoxy silane. The composites were prepared by using a Thermo Haake Rheomixer. Effect of filler loading and treatment of FA with silane coupling agent on mechanical and morphological properties were investigated and it was found that silane treatment indicated significant improvements on the mechanical properties of the HDPE‐FA composites. The improvement with silane treatment of FA was also confirmed by applying the Pukanszky model. Scanning electron microscopy on the fracture surface of composites had given direct evidence of better interfacial adhesion via silane treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4460–4467, 2006     

Studies on the Water Absorption of Bamboo-Epoxy Composites: The Effect of Silane Treatment

The effect of silane treatments on the water absorption properties of bamboo matting reinforced epoxy composites were investigated. Treatments using γ-Aminopropyltriethoxy silane, 3-trimethoxysilylpropyl methacrylate, Vinyltris(2-methoxyethoxy)silane, Bis[3-(triethoxysilyl)propyl] tetrasulfide, 3-aminopropyltrimethoxy silane and n-Octyltrimethoxy silane were carried out to study the water absorption property of the bamboo composites. Water absorption in the composites was studied by long-term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Only aminosilanes have shown the positive effects, but to a limited degree. It has been found that among the various silanes used only aminopropyltriethoxy silane treatment is suitable for bamboo-epoxy composite. Aminopropyltriethoxy silane-treated bamboo fiber composite has decreased the water uptake from 41.42% to 36.87%.     

Effect of silane coupling agent on the dielectric and thermal properties of DGEBA-forsterite composites

Diglycidyl ether of bisphenol A (DGEBA) -forsterite composites have been prepared through mechanical mixing process and the influence of silane coupling agent on the microstructure, dielectric and thermal properties were studied. Phase pure forsterite (Mg₂SiO₄) powder was prepared through solid state ceramic route. Filling fraction of forsterite in DGEBA matrix was varied from 10 to 40 vol%. The morphology and filler distribution of filled composite were studied by Scanning Electron Microscopy. Waveguide cavity perturbation technique was employed to measure the dielectric properties of composites. It is found that aminosilane treatment increased the dielectric constant and dielectric loss of the composites in both microwave and radio frequency ranges compared to composites prepared using untreated powders. Coefficient of thermal expansion of composites decreased with the forsterite addition and attains a relatively low value of 45 ppm/°C for composite containing 40 vol% surface treated filler.     

Mechanical,dynamic mechanical,and thermal characterization of fly ash and nanostructured fly ash‐waste polyethylene/high‐density polyethylene blend composites

Disposal of polyethylene used as carry bags is the greatest challenge increasing day by day. Composite materials were prepared by mixing Fly ash (FA) and nanostructured fly ash (NFA) from thermal power station as filler and blends of Waste polyethylene (WPE)(carry bags) collected from municipal solid waste (MSW) with virgin high‐density polyethylene (HDPE) as matrix. Different modifications were induced to improve the overall properties of these composites. At first, the WPE/HDPE blend matrix was modified by grafting with maleic anhydride (MA) and the composite prepared with FA/NFA. Then, the WPE/HDPE‐FA/NFA composite as a whole was treated with electron beam irradiation at 250 kGy radiation dose and finally the FA/NFA filler was treated with radiation dose of 250 kGy and the composite prepared. Significant enhancement in tensile strength, flexural strength, flexural modulus, and hardness are observed for MA modified and irradiated composites, the increase being more prominent in irradiated composites. Furthermore, an increase in storage/loss moduli with enhanced thermal stability was observed with the addition of FA/NFA and upon modifications. The analysis of the tensile fractured surfaces by scanning electron microscopy was in well correlation with the mechanical properties obtained. In summary, after analyzing the effects of the three different modifications on mechanical, dynamic mechanical and thermal properties, the irradiation on to the WPE/HDPE‐FA/NFA composites investigated was selected as the most appropriate for future applications. POLYM. COMPOS., 37:3256–3268, 2016. © 2015 Society of Plastics Engineers     

Physical properties and morphology of polycaprolactone/starch/pine‐leaf composites

Polycaprolactone (PCL)/starch and PCL/starch/pine‐leaf composites, which can be possibly applied as biodegradable food packaging materials with natural pine flavor, were prepared and characterized in this study. The effect of incorporating a silane coupling agent at different content levels on the physical properties and morphology of the composites was studied. To investigate the melting behavior of the composites, a differential scanning calorimetry was employed. A universal testing machine was used to investigate the tensile properties of the composites and the water absorption properties of the composites were also investigated. Scanning electron microscope was used to investigate the morphology of the composites. The physical properties and morphology of the PCL/starch and PCL/starch/pine‐leaf composites were largely affected by the composition, especially the content of the silane coupling agent. The silane coupling agent led to a much better interfacial compatibility between the PCL matrix and the fillers and resulted in better physical properties of the composites. The PCL/starch/pine‐leaf composite with the silane coupling agent showed a morphology, indicating a good interfacial adhesion between the PCL matrix and the fillers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 928–934, 2007     

Effect of environmental stress on the mechanical properties of surface treated fly‐ash/polyester particulate composite

Fly‐ash (FA) was surface treated with silane coupling agents (CA) vinyltriethoxy silane and aminopropyltrimethoxysilane. Fly‐ash/polyester (FA/GPR) and surface treated fly‐ash/polyester (FA/CA/GPR) particulate composites were made. The composites were exposed to various adverse environmental conditions such as water, boiling water, salt water, acid, alkali, toluene, weather and freezing–thawing cycles for 30 days. The mechanical properties, ie tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus, compressive strength, impact strength and hardness of FA/GPR and FA/CA/GPR were studied before and after exposure to adverse environmental conditions. The results indicate that the mechanical properties of FA/GPR composites are improved by surface treatment of FA and that their resistance to the various environmental stresses is also enhanced substantially by surface treatment. © 2002 Society of Chemical Industry     

Viscoelastic,mechanical, and thermal characterization of fly ash‐filled ABS composites and comparison of fly ash surface treatments

In the present investigation, viscoelastic, mechanical, thermal properties, and microstructural analysis of ABS reinforced with various surface treated fly ash (FA) has been studied. FA particles were surface treated with various chemical reagents, i.e., Ca(OH)₂, NaOH, and Bis(3‐triethoxysilylpropyl)tetrasulfane (Si69) to improve the interfacial adhesion between ABS and FA. DMA tests confirmed an increase in the stiffness in the surface treated composites. Hybrid ABS/FA composites showed optimum storage modulus and T_g as compared with the virgin matrix. TGA analysis also showed higher thermal stability of ABS/FA composites than virgin matrix with the surface treatments of FA. The treated FA composites also show improved mechanical properties compared to untreated FA composite. The morphology of virgin matrix, untreated and treated FA composites was studied employing SEM. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Unsaturated polyester‐toughened epoxy composites: Effect of sisal fiber on thermal and dynamic mechanical properties

In the present study, the mechanical and thermal properties of sisal fiber‐reinforced unsaturated polyester (UP)‐toughened epoxy composites were investigated. The sisal fibers were chemically treated with alkali (NaOH) and silane solutions in order to improve the interfacial interaction between fibers and matrix. The chemical composition of resins and fibers was identified by using Fourier‐transform infrared spectroscopy. The UP‐toughened epoxy blends were obtained by mixing UP (5, 10, and 15 wt%) into the epoxy resin. The fiber‐reinforced composites were prepared by incorporating sisal fibers (10, 20, and 30 wt%) within the optimized UP‐toughened epoxy blend. Scanning electron microscopy was used to analyze the morphological changes of the fibers and the adhesion between the fibers and the UP‐toughened epoxy system. The results showed that the tensile and flexural strength of (alkali‐silane)‐treated fiber (30 wt%) ‐reinforced composites increased by 83% and 55%, respectively, as compared with that of UP‐toughened epoxy blend. Moreover, thermogravimetric analysis revealed that the (alkali‐silane)‐treated fiber and its composite exhibited higher thermal stability than the untreated and alkali‐treated fiber systems. An increase in storage modulus and glass transition temperature was observed for the UP‐toughened epoxy matrix on reinforcement with treated fibers. The water uptake behavior of both alkali and alkali‐silane‐treated fiber‐reinforced composites is found to be less as compared with the untreated fiber‐reinforced composite. J. VINYL ADDIT. TECHNOL., 23:188–199, 2017. © 2015 Society of Plastics Engineers     

桦木纤维/不饱和聚酯复合材料制备与性能研究

采用硅烷偶联剂、乙醇和水等分别对桦木纤维(BF)和回收纸浆纤维进行表面处理,并分别将改性纤维作为不饱和聚酯树脂(UPR)的增强材料,制备相应的BF/UPR复合材料。研究了不同改性方法对复合材料界面性能的影响。结果表明:不同纤维种类、不同纤维表面处理方法和不同纤维用量对复合材料的界面性能、力学性能等影响较大;经硅烷偶联剂处理后的BF,可有效改善BF与UPR之间的界面相容性;当w(偶联剂处理BF)=16%时,相应复合材料的拉伸强度和冲击强度比纯UPR体系分别提高了31.0%和28.5%;在制备回收纤维/UPR复合材料之前应先对回收材料进行筛选,并且应优先选择对UPR基体树脂具有明显增强作用的回收纤维。     

Synthesis and application of multilayered core shell particles for toughening of unsaturated polyester resin

Toughening particles, comprising two radially alternating rubbery and glassy layers, were prepared by using sequential emulsion polymerization. The conditions which led to controlled particle size and morphology are discussed. A relatively new type of inert core shell particle [fly‐ash (FA)] and surface‐activated FA, by two different silane coupling agents, namely 3‐aminopropyltrimethoxy silane (AMP) and vinyltriethoxysilane (VES)‐based multilayered toughening particles, which radially comprise rubbery and glassy layers, were also prepared. The toughening particles were used with general purpose polyester resin (GPR) for making composite sheets. Formation of multiple layers in the core‐shell particles and their morphology were confirmed by transmission electron microscopy (TEM). The mechanical properties such as tensile, flexural, impact, and hardness of the toughened GPR are discussed critically. The tensile fractured surfaces were studied by scanning electron microscopy (SEM). Thermal property such as thermogravimetric analysis (TGA) were also discussed. The composites were exposed to various adverse environmental conditions such as water, boiling water, salt water, acid, alkali, toluene, weather, and freezing–thawing for 30 days. The mechanical properties (viz. the tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus, impact strength and hardness of FA/GPR, FA.AMP core/GPR, and FA.VEScore/GPR) were studied before and after exposure to adverse environmental conditions. The results indicate that the mechanical properties of FA/GPR composite are improved by surface treatment of FA and their resistance to the various environmental stresses is also enhanced substantially on modification by toughening particles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 511–528, 2004     

Kenaf fiber‐reinforced copolyester biocomposites

In this study the morphology and properties of a biodegradable aliphatic–aromatic copolyester mixed with kenaf fiber were investigated. Untreated kenaf fiber, as well as kenaf fiber treated with NaOH, and with NaOH followed by silane coupling agent treatment at various concentrations, were used as fillers in the composites. The biocomposites were prepared by melt‐mixing and a 10 wt% fiber loading was used for all the composites. The properties of the biocomposites were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile properties, environmental scanning electron microscopy (ESEM), and biodegradability. The extent of silane initiated grafting was followed by gel content determination. The presence of fiber and fiber treatment influenced the determined properties in a variety of ways, but the best balance of properties were found for the copolyester mixed with alkali‐treated fiber. This composite showed improved thermal, thermomechanical, and mechanical properties. The introduction of alkali treatment caused increased surface roughness in the fiber, which resulted in mechanical interlocking between the filler and the matrix, while silane treatment slightly reduced the properties. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Studies on Water Absorption of Bamboo-Polyester Composites: Effect of Silane Treatment of Mercerized Bamboo

The effect of silane treatments on the water absorption properties of mercerized bamboo matting reinforced polyester composites were investigated. Treatments using γ-Aminopropyltriethoxy silane, 3-trimethoxysilylpropyl methacrylate, Vinyltris(2-methoxyethoxy)silane, Bis[3-(triethoxysilyl)propyl] tetrasulfide, 3-aminopropyltrimethoxy silane and n-Octyltrimethoxy silane were carried out to improve the water resistant property of the bamboo fibers. Water absorption in the composites was studied by long-term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 51% to 35%. Further reduction is observed with silane treatment. Water absorption varies between 19% and 44%, the minimum being for aminopropyl triethoxy silane-treated composites.     

The surface modification of diatomite,thermal, and mechanical properties of poly(vinyl chloride)/diatomite composites

Pristine diatomite was first purified by acid treatment and then modified with γ‐methacryloxy propyl trimethoxysilane molecule (KH570) to introduce hydrophobic chains on the surface of acid‐treated diatomite. Fourier‐transform infrared spectroscopy and thermogravimetric analysis (TGA) indicated that the silane coupling agent (KH570) was successfully grafted on the diatomite through covalent bonding. The digital photos showed that the silanization process changed the surface property of the diatomite. The poly(vinyl chloride) (PVC)/pristine diatomite and PVC/modified diatomite composites were prepared via two‐roll mill. The thermal stability and mechanical properties of PVC composites were investigated by TGA, mechanical properties tests, and dynamic mechanical analysis. The results showed that the thermal stability of the composites improved and maximum weight loss temperature (T_max) of the PVC composite with 1 phr modified diatomite was about 20°C higher than that of PVC composite without diatomite. The PVC/modified diatomite composites exhibited better mechanical properties owing to the stronger interfacial interaction between PVC matrix and modified diatomite. But the impact strength reduced sharply when the addition of diatomite was more than 1 phr. The reason of the phenomenon is that the diatomite plays the role of defects in PVC and it works against the absorption of impact strength energy. It was proved by the results of scanning electron microscopy. J. VINYL ADDIT. TECHNOL., 25:E39–E47, 2019. © 2018 Society of Plastics Engineers     

Effect of the silane modification of an organoclay on the properties of polypropylene/clay composites

A commercial clay, Cloisite®20A (C20A) was modified with three different silane compounds, propyltrimethoxy silane, octyltrimethoxy silane, and octadecyltrimethoxy silane, to control the hydrophobicity of C20A. The amount of the silane compounds grafted to C20A was quantified from the weight loss by using TGA, and the hydrophobicity was evaluated by the amount of water absorption. The variation of the interlayer distance was traced by XRD and TEM observation. SEM/EDS was employed to visualize the morphology of the fractured surface and the degree of dispersion of the clay layers in the PP/clay composites. Measurements of the tensile properties of the PP/clay composites indicated that the composite made from PP and the C20A modified with octadecyltrimethoxy silane exhibited the most excellent tensile properties. This was ascribed to the fact that the C20A modified with octadecyltrimethoxy silane possessed the most favorable interfacial interaction with PP and thus the degree of dispersion of the clay layers was the best in the PP matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Properties Enhancement of Mengkuang Leaf Fiber/Ethylene‐Vinyl Acetate/Natural Rubber Thermoplastic Elastomer Composites by Alkaline Peroxide Bleaching Treatment

In this article, the effect of alkaline peroxide bleaching treatment using hydrogen peroxide on mengkuang leaf fiber (MLF) to the tensile, thermal properties and water absorption of thermoplastic elastomer composites based on ethylene‐vinyl acetate/natural rubber and MLF was investigated. Fiber morphology and the fiber‐matrix interface were further characterized by scanning electron microscopy (SEM). Treated composites showed better tensile properties than untreated fiber composites. SEM of the fractured surfaces of the composite specimens indicates that the bleaching treatment improved the interfacial interaction between the fiber and the matrix. The results of thermogravimetric analysis showed a higher thermal stability for treated composites than untreated composites. Furthermore, alkaline bleaching treatment has resulted in reduction of water absorption from 31% to 26% as compared with untreated composites. J. VINYL ADDIT. TECHNOL., 26:127–134, 2020. © 2019 Society of Plastics Engineers     

Effect of bamboo fibers with different coupling agents on the properties of poly(hydroxybutyrate-co-valerate) biocomposites

Green biocomposites were prepared via injection molding with poly(hydroxybutyrate-co-valerate) and natural bamboo fibers. Three types of coupling agents were used to modify the fibers, and the influence of different kinds of coupling agents was evaluated. The mechanical properties of the biocomposites varied with the type and content of the coupling agents. The water absorption and thermal properties of the composites were measured simultaneously after treatment with the coupling agents. Fourier transform infrared spectroscopy was employed to analyze the principle of fiber treatment with different coupling agents. The mechanical properties of the composites markedly improved, whereas the water absorption decreased after modification. Treatment with coupling agents only slightly influences the thermal properties but improved the crystallinity of the composites. Therefore, the interfacial compatibility between the fiber and matrix was enhanced after modification, with the silane coupling agent exhibiting the best effect. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47533.     

Bamboo fiber reinforced thermosetting resin composites: Effect of graft copolymerization of fiber with methacrylamide

Epoxy and polyester resins have been reinforced with methacrylamide (MAA) treated bamboo strip matting to develop bamboo fiber reinforced plastic composites. Bamboo mats were graft copolymerized with 1, 3, and 5% solution of MAA. The mechanical (tensile strength, elastic modulus, flexural strength, and flexural modulus), thermal, and water absorption properties of the composites were determined. One percent treatment of bamboo with MAA gave optimum results with epoxy resin. The mechanical properties were improved. TGA results reveal that the degradation temperature of the composite has improved after grafting. The weight loss of 1% MAA treated bamboo–epoxy composite reached a value of 95.132% at 795°C compared to 97.655% at 685°C of untreated bamboo–epoxy composite. Water absorption in the composites was studied by long term immersion and 2 h boiling in distilled water. The process of water absorption indicates Fickian mode of diffusion. MAA treatment results in reduced water uptake. There was improvement in the properties of pretreated bamboo‐polyester matrix composite as well. Three percent treatment of bamboo with MAA gave optimum results with polyester resin. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

硅烷偶联剂KH-550和Si-69增容粉煤灰/废胶粉复合材料

采用硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH-550)和双-[γ-(三乙氧基硅)丙基]四硫化物(Si-69)对粉煤灰(FA)/废胶粉(URP)复合材料进行增容,考察了偶联剂用量和加入方式对复合材料性能的影响,并对复合材料的结构和微观形貌进行了表征。结果表明,KH-550和Si-69均可以改善FA与URP的相容性,提高复合材料的力学性能;Si-69的增容效果好于KH-550,最佳的Si-69/FA/URP(质量比)为1.0/40/100。采用硅烷偶联剂与FA混合、再与URP混合的分步加入方式,与同步加入方式相比,制备的复合材料更易成型,且复合材料的力学性能、耐磨性能和耐热老化性能更好。与KH-550相比,用Si-69改性的FA/URP复合材料,其相界面更为模糊,无孔洞。硅烷偶联剂改性的FA/URP复合材料中有Si—O生成。     

Effect of hybridization and chemical modification on the water‐absorption behavior of banana fiber–reinforced polyester composites

The water sorption characteristics of banana fiber–reinforced polyester composites were studied by immersion in distilled water at 28, 50, 70, and 90°C. The effect of hybridization with glass fiber and the chemical modification of the fiber on the water absorption properties of the prepared composites were also evaluated. In the case of hybrid composites, water uptake decreased with increase of glass fiber content. In the case of chemically modified fiber composites, water uptake was found to be dependent on the chemical treatment done on the fiber surface. Weight change profiles of the composites at higher temperature indicated that the diffusion is close to Fickian. The water absorption showed a multistage mechanism in all cases at lower temperatures. Chemical modification was found to affect the water uptake of the composite. Among the treated composites the lowest water uptake was observed for composites treated with silane A1100. Finally, parameters like diffusion, sorption, and permeability coefficients were determined. It was observed that equilibrium water uptake is dependent on the nature of the composite and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3856–3865, 2004