Mechanical and Thermal Analysis of Poly (Vinyl-Alcohol) and Modified Wood Dust Composites

Abstract

A study of Polymer Modified Wood Dust Nanocomposite (PMW) was done using a polymer matrix of poly (vinyl alcohol) (PVA) and Modified Wood Dust as reinforcing agent. Composite materials were prepared by effectively dispersing the wood dust within the PVA matrix via a conventional solvent casting technique. The obtained PMW materials were typically characterized by Fourier-Transformation infrared (FTIR) spectroscopy. The Thermal properties of the PWC films were investigated by means of Themogravimetric Analysis. The dispersion of modified filler in the polymer matrix was investigated by TEM analysis. The surface morphology of the uncrosslinked and crosslinked PVA nanocomposite membranes was analyzed by Tapping Mode—Atomic Force Microscopy (TM-AFM). To study the temperature dependencies of the dynamic moduli, stress relaxation, mechanical loss, and damping phenomena of the composite material, dynamic mechanical analysis (DMA) was done. The tensile behavior of the composite films was analyzed by comparing their tensile strength and their modulus of elasticity with change in filler content.     

Mechanical and Dynamic Analysis of Poly (Vinyl Alcohol)-Modified Inorganic Filler Composite

A study of polymer-acid-modified Red mud composite (PRC) was done using a polymer matrix of poly (vinyl alcohol) (PVA) and layered Red mud as reinforcing agent. Composite materials were prepared by effectively dispersing the PVA matrix into the inorganic layered modified Red mud via a conventional solvent-casting technique. The PRC materials, as synthesized, were typically characterized by Fourier-Transformation infrared (FTIR) spectroscopy. The nature of the PRC films was investigated by means of X-ray diffraction. The dispersion of modified filler in the polymer matrix was investigated by TEM analysis. To study the temperature dependencies of the dynamic modulii, stress relaxation, mechanical loss, and damping phenomena of the composite material, dynamic mechanical analysis (DMA) was done. The tensile behavior of the composite films was analyzed by comparing their tensile strength and their modulus of elasticity with change in filler content.     

Effect of Graphitic Nanosheets on the Physical Properties of Cyclic Olefin Copolymer Composite Films

In this study, microstructural and physical properties of cyclic olefin copolymer composite films prepared by melt processing method and using of graphitic nanofillers, namely, graphite, graphite oxide, and reduced graphite oxide were investigated. Structural and physical properties of the chemically modified graphites and composite films were characterized by the Fourier transform infrared, X-ray diffractometer, scanning electron microscopy, dynamic mechanical analyzer, and thermogravimetric analyzer methods. It was found that the composite films including reduced graphite oxide exhibited exfoliated structure whereas graphite- and graphite oxide-based films showed intercalated structure. It was also obtained that all composite films showed superior gas barrier performance compared to the cyclic olefin copolymer.     

Chitosan‐finished Antheraea mylitta silk fibroin nonwoven composite films for wound dressing

In this study, we aimed to produce nonwoven wound‐dressing films made of Antheraea mylitta (tasar) silk fibroin by a solution‐casting method. These nonwoven films were finished with chitosan solutions of different concentrations ranging from 0.75 to 2% w/v with a pad–dry method to fabricate nonwoven composite films. Chitosan‐finished tasar fibroin nonwoven composite films (CMTFFs) showed higher mechanical and dynamic mechanical properties as compared to nonwoven tasar fibroin. The physical, structural, and thermal properties of the films were investigated. The hemocompatibility, cytocompatibility, and biodegradation tests showed that the CMTFF was a promising material for use as a wound dressing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44341.     

Flexible and compatible polymer composite blends based on polyurethane/sodium ionomer/lignin and their properties

Polyurethane, sodium ionomer (Surlyn 8150), and lignin (PSL)-based composite films were prepared by the solution casting method with different weight percentages of lignin. The relationships among the morphology, thermal resistance, mechanical, and dynamic mechanical properties for all composites were characterized. The structural interactions, microstructure, and optical properties of the composite were studied by Fourier transform infrared, scanning electron microscopy (SEM), X-ray diffraction, and ultraviolet (UV) spectroscopy. The mechanical and UV absorbance properties of the composite films improved significantly with the addition of lignin particles. The tensile strength increased from 42.5 to 57.2 MPa. Dynamic mechanical analysis results show that the storage modulus of the composites increased and exhibited a single T_g. PSL composite films show excellent water barrier properties, with improved surface hydrophobicity. SEM images revealed that a relatively uniform phase morphology and good interfacial compatibilization wereachieved. These results suggest that all of the composite films with PU, Na ionomers, and lignin materials exhibited good compatibility and miscibility. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48885.     

Polyvinyl alcohol fuller's earth clay nanocomposite films

Nano fuller's earth was prepared by milling and subsequent sonication of clay. The polyvinyl alcohol (PVA) and PVA ‐Nano clay composite films were prepared by solution casting method. The films were characterized for their structural, mechanical, and thermal properties using electron microscopes (SEM, TEM), Tensile Tester, dynamic mechanical analyzer (DMA), thermo gravimetric analyzer (TGA), and Raman spectroscopy. The nanocomposite films showed improvement in mechanical properties, viscoelastic behavior as well as resistance towards thermal degradation. Uniform distribution of clay due to intimate interaction between clay and polymer appears to be the cause for improved properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of bacterial cellulose/graphene oxide composite films using dyeing method

In this study, bacterial cellulose (BC) hydrogels were cultured from a kombucha SCOBY starter. The scanning electron microscopy (SEM) results indicated that the dried BC exhibited an interpenetrating fibrous mat. The BC films harvested for 5, 10, and 15 days were 15–19, 14.4–24, and 30–31 μm thick, respectively. Then, BC/graphene oxide (GO) composite films were prepared via the exhaust dyeing method. GO sheets penetrated the BC matrix, resulting in the formation of a BC/GO composite, as revealed by the SEM analysis results. The mechanical properties of the composite films were investigated. Compared with virgin BC, the tensile strength of the composite films was higher, while the %E at break was lower, resulting in a significant increase in the Young's modulus. The X-ray diffraction results indicated that an increase in the dyeing time (0.5–2 h) gradually induced cellulose crystalline conformation, which in turn affected the swelling ability, mechanical properties, and electrical properties of the BC/GO composite films. After the reduction of GO to reduced GO (rGO), flexible conductive BC/rGO films were obtained, as confirmed by their resistivity values. Thus, flexible conductive composite films with excellent mechanical properties were successfully fabricated.     

Green Composites: Development of Poly(Vinyl Alcohol)-Wood Dust Composites

As part of an ongoing research on biodegradable composites, which can be aptly termed as green composites, the present article reports on the incorporation of wood industry waste material, wood dust, as organic filler in film matrix based on Poly(Vinyl Alcohol) as continuous phase. In this study as filler, dust of Piyasal wood was used. In order to improve the compatibility between wood dust and plastic material, different amounts of cross-linking agents, such as glutaraldehyde, were used and the effect of these on water absorption and biodegradability was studied. The as-synthesized PVA-Wood dust composite materials are typically characterized by Fourier-Transformation Infrared (FTIR) spectroscopy and, wide-angle x-ray diffraction. The mechanical analysis of the composite material was studied by tensile test. The morphological image of as-synthesized materials was studied by optical microscope (OM).     

Morphologies and applied properties of free radical/cationic UV‐cured CPUA/TMPTMA/CER composite films

A UV‐cured composite film was prepared by free free‐radical photopolymerization from a blend containing oligomer cycloaliphatic polyurethane acrylate (CPUA) and reactive diluent trimethylolpropane trimethaacrylate (TMPTMA) with the same weight (coded as UT) in the presence of free free‐radical photoinitiator Irgacure 754. It was proved to be a homogeneous system featuring only one phase by means of scanning electron microscopy (SEM). Cycloaliphatic epoxy resin (CER) was introduced to enhance mechanical properties of the UV‐cured UT composite film in the presence of cationic photoinitiator Irgacure 250, and a series of UV‐cured CPUA/TMPTMA/CER composite films with different component ratios were prepared by free radical/cationic hybrid UV UV‐curing technique. Results of conversion curves, SEM, and Fourier‐ transform infrared spectroscopy illustrated that UT was cured faster than CER, leading to dynamically asymmetric photopolymerization‐induced phase ‐separation behaviors. The thermal and mechanical properties were evaluated via thermal degradation analysis, dynamic mechanical analysis, and stress–strain curves. Surface properties such as pencil hardness, pendulum hardness, shrinkage rate, contact angle, flexibility, and glossiness were also studied. All these measurements revealed that component ratios, intermolecular attractions, photopolymerization velocities, and viscosities had remarkably influenced on the morphologies and applied properties of UV‐cured composite films, and interpenetrating polymer network films had better comprehensive performances than other UV‐cured composite films with different microstructures. POLYM. COMPOS., 36:1177–1185, 2015. © 2014 Society of Plastics Engineers     

Solid‐state recycling of polyimide film waste

Possibility of the polyimide (PI) films waste recycling by solid‐state mechanochemistry was investigated in this study. Obtained PI powder was used for development of thermostable blends and multicomponent tribocompositions, which include additions of carbon black, ultradispersive diamond powder, and quasicrystalls. PI films waste treatment was provided in high‐energy planetary ball mill. Powder compositions were mixed by low‐energy planetary ball mill. Bulk samples were obtained by compression molding. Structural and thermal properties of initial polymers and composite materials were determined from scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis and fourier transform infrared spectroscopy. Tribological tests of composite materials were provided in dry sliding regime on “pin‐on‐disk” tribometer. Finally, optimal regimes of polymer composite materials producing were obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Novel low-κ polyimide/mesoporous silica composite films: Preparation,microstructure, and properties

A series of novel low-dielectric constant (low-κ) polyimide (PI) composite films containing the SBA-15 or the SBA-16-type mesoporous silica were successfully prepared via in situ polymerization and following thermal imidization. Their morphologies, dielectric constants, and thermal and dynamic mechanical properties were investigated. It is found that the dielectric constants of the composite films can be reduced from 3.34 of the pure PI to 2.73 and 2.61 by incorporating 3 wt% SBA-15 and 7 wt% SBA-16, respectively. The reduction of the dielectric constant is attributed to the incorporation of the air voids (κ = 1) stored within the mesoporous silica materials, the air volume existing in the gaps on the interfaces between the mesoporous silica and the PI matrix, and the free volume created by introducing large-sized domains. The PI/mesoporous silica composite films prepared in this study also present stable dielectric constants across the wide frequency range and a good phase interconnection. The improvement of the thermal stability and dynamic mechanical properties of the PI film is achieved by incorporation of the mesoporous silica materials. The enhanced interfacial interaction between the surface-treated mesoporous silica and the PI matrix has led to the minimization of the deterioration of the mechanical properties. The incorporation of the mesoporous silica materials is a promising approach to prepare the low-κ PI films.     

Synthesis and mechanical properties of carbon nanotube/diamond-like carbon composite films

Diamond-like carbon (DLC) coatings were successfully deposited on carbon nanotube (CNT) films with CNT densities of 1 × 10⁹/cm², 3 × 10⁹/cm², and 7 × 10⁹/cm² by a radio frequency plasma-enhanced chemical vapor deposition (CVD). The new composite films consisting of CNT/DLC were synthesized to improve the mechanical properties of DLC coatings especially for toughness. To compare those of the CNT/DLC composite films, the deposition of a DLC coating on a silicon oxide substrate was also carried out. A dynamic ultra micro hardness tester and a ball-on-disk type friction tester were used to investigate the mechanical properties of the CNT/DLC composite films. A scanning electron microscopic (SEM) image of the indentation region of the CNT/DLC composite film showed a triangle shape of the indenter, however, chippings of the DLC coating were observed in the indentation region. This result suggests the improvement of the toughness of the CNT/DLC composite films. The elastic modulus and dynamic hardness of the CNT/DLC composite films decreased linearly with the increase of their CNT density. Friction coefficients of all the CNT/DLC composite films were close to that of the DLC coating.     

芳纶纳米纤维增强聚乙烯醇复合膜的制备与性能

以芳纶纤维Kevlar@49为原料,在温和条件下制备了芳纶纳米纤维分散体(ANFS),并利用分散体制备了芳纶纳米纤维/聚乙烯醇(ANFs/PVA)复合膜。通过傅里叶红外光谱(FTIR)仪、差示扫描量热(DSC)仪、原子力显微镜(AFM)、扫描电子显微镜(SEM)、电子万能试验机及透光度/雾度测定仪等考察了复合膜的微观结构、热学、光学及力学性能。FTIR证明,复合膜中ANFs与PVA具有一定的分子间氢键作用,促进了ANFs在PVA基体中的分散。由AFM和SEM可以清晰观察到直径为20~30 nm的芳纶纳米纤维分散体,并且通过SEM观察到复合膜表面较为平整。当芳纶纳米纤维质量分数为6.0%时,复合膜的抗拉强度为17.86 MPa,断裂伸长率为442%;透光度为82.63%,雾度为27.56%;玻璃化温度,熔融温度和结晶温度分别为75.20、208.82和174.51℃,表明其透光性良好,力学和热学性能达到最佳。     

碳化钛/聚酰亚胺高介电复合薄膜的制备及性能研究

采用机械共混法将经硅烷偶联剂改性的碳化钛粉体掺杂入聚酰亚胺中,制备了碳化钛/聚酰亚胺复合薄膜。分析了不同碳化钛粒子含量对复合薄膜的显微结构、力学性能及介电性能的影响。实验结果表明,随着纳米TiC含量的不断升高,复合薄膜的拉伸强度呈现先上升后下降的趋势,复合薄膜的耐电击穿场强迅速下降。与此同时,复合材料的介电常数则显著提高。     

Preparation of gelatin-based films modified with nanocrystalline cellulose

Gelatin is a natural biological macromolecule derived from the collagen in the connective tissue of the skin, bone and other tissues. It has been widely used in medicine, food and industrial production and other fields for easy molding, excellent compatibility and biodegradability. However, physical and chemical disadvantages impede its further application, seriously. Therefore, modification of the gelatin films becomes more and more important. In this study, the gelatin/nanocrystalline cellulose (NCC) composite films were prepared by casting method with 4% glycerol as plasticizer. The effect of NCC on the properties of the composite films was investigated by the characterization of its morphology and mechanical, thermal, and optical properties and water adsorption. The results showed that mechanical, thermal stability and water absorption properties of the gelatin/NCC composite film were obviously improved. The composite films showed the highest tensile strength (13.56?±?0.25 MPa) when the mass concentration of NCC was 0.6%. Adding NCC to gelatin benefited the thermal stability of composite films. The gelatin/NCC composite film of 0.4% NCC had the highest melting transition temperature (138.9 °C). The composite films exhibited the lower water absorption (271.1%) when mass concentration of NCC was 1.0%. Thus, these results indicated that NCC could affect the properties of gelatin-based composite films, and showed it has potential for application in food packing.     

Composites made from a soybean oil biopolyurethane and cellulose nanocrystals

Cellulose nanocrystals (CNC) obtained by acidic hydrolysis from microcrystalline cellulose were dispersed in a biopolyurethane matrix to prepare composite films. The polyurethane was prepared from a hydroxylated soybean oil (SO‐OH) and a polymeric diphenyldiisocyanate (pMDI), using a organotin compound as the catalyst. The composite films contained different concentrations of nanocelullose, without any macroscopic aggregates in all cases. Thermal, tensile and dynamic mechanical properties of the films were determined for all the samples. In particular, it was observed that the glass transition temperature of the nanocomposites slightly increased with the concentration of the cellulose nanocrystals. The nanocomposite with 1 wt% of nanocellulose showed the highest tensile strength of the series. POLYM. ENG. SCI., 58:125–132, 2018. © 2017 Society of Plastics Engineers     

Preparation and characterization of starch-based composite films reinforced by apricot and walnut shells

Starch-based biodegradable films were prepared by using solution-casting method and reinforced by agricultural residues [apricot and walnut shell (APS and WNS) powder]. The powder of both shells was added in different ratios (0, 2.5, 5, 7.5, and 10%) to investigate the microstructures and performances (mechanical and thermal properties) of the starch-based film. Different techniques such as impact, tensile testing, scanning electron microscope, optical microscope (OM), X-ray diffraction (XRD), water vapor transmission rate (WVTR), and dynamic mechanical analysis were applied to study the thermomechanical and barrier properties of the composite films. Results showed that the incorporation of both shells significantly improved the WVTR and mechanical properties of starch-based films. The shells powder was significantly increased the Young's modulus and tensile strength of the starch-based films. Both OM and SEM results showed reasonably good compatibility between starch and reinforced shells. OM and XRD indicated that the APS and WNS not only retained their crystalline structure in the film but they also strengthened the peak intensity of the film. This phenomenon can be used to explain the mechanism of mechanical reinforcement. Since all the components used in the preparation of the films are food grade ingredients, it is expected that the films developed in this work will be used for food packaging applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47978.     

Organic/Inorganic Hybrid Composite Films from Polyimide and Organosilica: Effect of the Type of Organosilica Precursors

We report the influence of the type of organosilica precursors on the growth of organosilica domains and the interfacial interaction between polyimide (PI) and organosilica in PI/organosilica hybrid composite films. The organosilica precursors used are tetraethoxysilane (TEOS), triethoxy(ethyl)silane (TEES), and 1,2-bis(triethoxysilyl)ethane (BTSE). The hybrid composite films were prepared by thermal imization of the precursor films that were made via sol-gel process of the mixture of poly(4,4’-oxydianiline benzenetetracarboxamic acid) (PMDA-ODA PAA) and organosilica precursors. The hybrid composite films were characterized using Fourier transform infrared (FT-IR) spectra, ²⁹Si cross polarization (CP) MAS-NMR spectra, field emission-scanning electron microscopy (FE-SEM), UV-visible spectra, small angle x-ray scattering (SAXS), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results showed that the TEES precursor was more pronounced in improving the interaction of corresponding organosilica with PI than other precursors.     

Clay induced thermoplastic crystals in thermoset matrix: Thermal,Dynamic mechanical,and morphological analysis of clay/nylon‐6‐epoxy nanocomposites

A novel procedure to synthesize in situ clay/nylon‐6 composite suspension was explored via anionic solution polymerization. The suspension was efficiently blended with water‐based epoxy resin using mechanical stirrer at room temperature. Hence, a 3‐component coating system was obtained consisting of nano‐clay, nylon‐6 and epoxy resin. Large number of coatings and films were prepared with variation in clay and nylon‐6 loading. Concentration of clay was found to have profound effect on crystallinity of nylon‐6, thereby affecting the overall properties of clay/nylon/epoxy composite. All the films were characterized for thermal and dynamic mechanical behavior using differential scanning calorimeter (DSC) and dynamic mechanical analysis (DMA). Lower amount of clay was found to increase the crystallinity of nylon‐6 which in turn increased the plasticization of epoxy resin indicated by reduction in T_g. A multiphase morphology with distinct amorphous and crystalline zones was observed under scanning electron microscopy (SEM). A remarkable symmetrical morphology with branched dendritic crystal structure was observed for few of the clay/nylon/epoxy system. POLYM. COMPOS., 37:2206–2217, 2016. © 2015 Society of Plastics Engineers     

Crosslinked carboxylated SBR composites reinforced with chitin nanocrystals

This study aims to develop and characterize the nanocomposites using sulfur cross-linked carboxylated styrene-butadiene rubbers (S-xSBR) as the matrix and chitin nanocrystals (CNCs) as nanofillers. The composites’ morphology and properties were examined by light transmittances, fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic mechanical analysis (DMA), thermo gravimetric analyzer (TGA), and tensile properties determination. The addition of CNCs has slight effect on transparency of the composite films. FTIR data confirm the interfacial interactions between CNCs and S-xSBR via hydrogen bonds. CNCs are uniformly dispersed in the matrix from SEM result. The addition of CNCs can significantly improve the tensile strength and modulus both in static and dynamic states. The tensile modulus and tensile strength of S-xSBR/CNCs composites with the 4 wt.% CNCs is 62.5 % and 97.6 % higher than that of pure S-xSBR. The storage modulus, glass transition temperature, and the thermal stability of the composites are higher than those of the neat S-xSBR. The mechanical properties of the composite films are water-responsive, as the swollen samples exhibit obviously decreased strength and modulus. The greatest mechanical contrast is shown in the S-xSBR/CNCs composites with 2 wt.% CNCs loading whose tensile modulus decrease from 60.4 to 6.1 MPa after swelling equilibrium. The significant reinforcement effect of CNCs on S-xSBR is attributed to the unique structure of CNCs and the interfacial interactions in the composite.