Thickness Swelling Behavior Research Articles

Solid particle erosion, water absorption and thickness swelling behavior of intra ply Kevlar/PALF fiber epoxy hybrid composites

AbstractIn this investigation, the different weaving pattern of intra ply Kevlar and pineapple leaf fiber (PALF) reinforced with epoxy hybrid composites was fabricated using the compression molding method. Solid particle erosion wear properties, water absorption, and thickness swelling behavior were tested. Solid particle erosion wear properties were tested using an air‐jet erosion tester. The various factors for solid particle erosion test were taken as impingement angle, exposure time, and weaving pattern. The weaving pattern was varied as plain type, twill type, basket type. The result showed that basket weave type and pure Kevlar fiber reinforced epoxy composites have better water absorption and thickness swelling properties. The results from the solid particle erosion test indicated that twill type and pure Kevlar fiber reinforced epoxy composites showed superior erosion wear resistance compared to other composites. Further, the statistical analysis was carried out using Taguchi analysis and their results showed that twill type Kevlar/PALF reinforced with epoxy composite was a minimum erosion wear rate at 90° of impingement angle and 6 min exposure time. The erosion mechanism of the surface eroded composite specimens was investigated using scanning electron microscopy.

Mechanical, Absorption and Swelling Properties of Vinyl Ester Based Natural Fibre Hybrid Composites

Natural fibres such as Banana (B), Jute (J) and Kenaf (K) were hybridized in different stacking sequences in vinyl ester. The composites with hybridized fibres were tested to evaluate their tensile, flexural and impact properties. Further, they were also tested for their water absorption and thickness swelling behavior. The hybridization of the fibre mats had an encouraging outcome on the mechanical behavior. The JKBKBJ hybrid composite possessed the maximum tensile strength (34.12 MPa) while maximum stiffness of 1.667 GPa was observed for the KBJJBK hybrid composites. The observations from the flexural testing indicated that the hybrid composites resisted the flexural load for higher displacement. All the hybrid configurations presented better impact strength over the composites reinforced with kenaf and jute fibres. Among the hybrid composites investigated, the KJBBJK hybrid composite displayed highest impact strength (12.32 kJ/m2). The improved strength, stiffness and lower moisture absorption properties make the composites with hybridized fibres a potential candidate for the light weight structural applications.

Effect of immidazolium-based green solvents on the moisture absorption and thickness swelling behavior of wood flour/polyethylene composites

The water transport kinetics and moisture-induced thickness swelling behavior of wood-plastic composites (WPCs) in the presence of two imidazolium-based ionic liquids (ILs) were studied. The wood flour chemically treated with ILs were compounded through melt mixing of high-density polyethylene and coupling agent, and finally, the test specimens were produced by compression molding. Hygroscopic rates of the composites were evaluated by immersing them in the water at room temperature and monitoring moisture sorption and thickness changes for several weeks. Besides, the water diffusion coefficients and swelling rate parameters were measured for all composites. It was found that the water absorption and thickness swelling of the WPC specimens reduced as a result of ILs treatment. The SEM analysis revealed that the presence of ILs can improve the quality of adhesion between the polymer matrix and the cellulosic materials, to decrease the gaps in the interfacial region and block the hydrophilic groups. Studying the water sorption process in the specimens showed that the process follows kinetics and mechanisms described by Fick’s law. The highest water diffusion coefficients and swelling rate parameters were found in composites with untreated wood.

Water transport kinetics and thickness swelling behavior of natural fiber-reinforced HDPE/CNT nanocomposites

Abstract This study mainly focused on investigating the effect of carbon nanotubes (CNTs) on the long-term hygroscopic behavior of composites based on old corrugated container (OCC) and high density polyethylene (HDPE). Composite profiles were made by melt compounding and then injection molding. For CNT as a reinforcing agent, different loading levels of 0, 1, 3 and 5 phc was used. The amount of HDPE and coupling agent was fixed at 50 wt% and 2 phc for all formulations, respectively. The governing kinetic behavior of water transport in the studied composites was examined by immersing them in water at room temperature for several weeks, and water diffusion coefficients were also calculated by evaluating the water absorption isotherms. In addition, a predictive model for determining the thickness swelling rate of the samples was developed by Shi and Gardner model. Results indicated that the composites filled with CNT had considerably lower water absorption compared with those samples without ones. The absorption processes for all families of composites were found to exhibit Fickian diffusion behavior. It was found that that equilibrium thickness swelling and also shorter equilibrium time (the time to reach the equilibrium thickness swelling) decreased with increase of CNT loading. Furthermore, the swelling model provided a good predictor of the hygroscopic thickness swelling process of HDPE/OCC/CNT hybrid composites. Also, a good linear relationship was fit between swelling rate parameter ( K SR ) and CNT contents. The minimum K SR values were observed in composites made of 5 phc CNT.

Water absorption and thickness swelling behavior of almond (Prunus amygdalus L.) shell particles and coconut (Cocos nucifera) fiber hybrid epoxy-based biocomposite

AbstractIn this research, the suitability of almond shell and coconut fiber as a renewable agricultural residue for the manufacturing of biocomposite to be used as a replacement of wood was investigated. The use of agriculture waste as a reinforcement in composite may result in several environmental and socioeconomic benefits. A biocomposite containing different weight percentages of almond shell particle (10, 20, 30, 40, and 50 wt%) and coconut fiber (2, 4, and 6 wt%) mixed with 20 wt% almond shell particles was made using epoxy resin and 0.5 wt% tricresyl phosphate. The water absorption (WA), thickness swelling (TS), and morphology [scanning electron microscopy (SEM)] test of the biocomposite were determined. The rate of WA is less in saline water (SW) compared to rainwater (RW). The influence of the addition of coconut fiber is more compared with the almond shell particles for both the WA and TS.

Effect of nanoclay on thickness swelling behavior in the extrusion foaming of wood flour/polyethylene composites

This study investigates the effect of nanoclay on the cell morphology and thickness swelling behavior in the extrusion foaming of wood flour/polyethylene composites with a chemical blowing agent. To meet this objective, the nanoclay, high-density polyethylene, and coupling agent were compounded and then the granules were mixed with wood flour and blowing agent in a twin-screw extruder. Consequently, foaming process was completed in the injection stage. The amount of wood flour was fixed at 50 wt% for all samples. For nanoclay and chemical blowing agent, different levels of 0, 2, 4 per hundred resins (phr) and 0, 0.5, 1, 1.5 phr were considered, respectively. The results indicate that the addition of clay generally reduces the cell size, increases the cell density, and facilitates foam expansion. Furthermore, the thickness swelling of the composite decreased with increase in nanoclay. The composites containing 1.5 phr of foaming agent exhibited higher thickness swelling value and swelling rate parameter ( KSR) than those containing nanoclay. The swelling model provided a good predictor of the hygroscopic thickness swelling process of wood flour/polyethylene/nanoclay hybrid foamed composites.

Effects of reprocessing on the hygroscopic behavior of natural fiber high-density polyethylene composites

Detailed analysis of the effects of recycling process on long-term water absorption, thickness swelling, and water desorption behavior of natural fiber high-density polyethylene composites is reported. Composite materials containing polyethylene and wood flour, rice hulls, or bagasse fibers and 2% compatibilizer were produced at constant fiber loading and were exposed to a simulated recycling process consisting of up to five times grinding and reprocessing under controlled conditions. A wide range of analytical methods including water absorption/desorption tests, thickness swelling tests, density measurement, scanning electron microscopy, image analysis, contact angle, fiber length analysis, Fourier transform infrared spectroscopy, and tensile tests were employed to understand the hygroscopic behavior of the recycled composites. Water absorption and thickness swelling behaviors were modeled using existing predictive models and a mathematical model was developed for water desorption at constant temperature. Results indicated that generally the recycled composites had considerably lower water absorption and thickness swellings as compared with the original composites which were attributed to changes in physical and chemical properties of the composites induced by the recycling process. Water desorption was found to be faster after recycling. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Hygroscopic thickness swelling rate of wood polymer nanocomposite

In this study, the effects of nanoclay and coupling agent content on the clay dispersion and thickness swelling behavior of PP/WF composites were investigated. To meet this objective, the blend nanocomposites were prepared by melt mixing PP and beech WF at 50% weight ratios, with various amounts of nanoclay (0, 3, and 6 phc) and MAPP (0, 2, and 4 phc) in Hakee internal mixer. The samples were then made by injection molding. The thickness swelling rate of the composites was evaluated by immersing them in water at room temperature for several weeks (up to 3000 h). A swelling model developed by Shi and Gardner (2006) was used to study the thickness swelling process of composites, from which the parameter, K SR, can be used to quantify the swelling rate. The results indicated that equilibrium thickness swelling and also shorter equilibrium time (the time to reach the equilibrium thickness swelling) decreased with increase of clay loading, and also the effect of compatibilizer was positive in terms of enhancing the dimensional stability of the composites. The swelling model developed was a good predictor of the hygroscopic swelling process of wood plastic composites. The composites containing PP had a higher KSR than those containing MAPP or nanoclay. The minimum KSR values were observed in composites made of 3 phc of nanoclay and 4 phc of MAPP. The micrographs of XRD and TEM confirmed the intercalation morphology in nanocomposite samples.

Recycled Natural Fiber Polypropylene Composites: Water Absorption/Desorption Kinetics and Dimensional Stability

Detailed analysis of the effects of recycling process on long-term water absorption, thickness swelling and water desorption behavior of natural fiber polypropylene composites is reported. Composite materials containing polypropylene and wood flour, rice hulls or bagasse fibers were produced at constant fiber loading and were exposed to a simulated recycling process consisting of up to five times grinding and reprocessing under controlled conditions. A wide range of analytical methods including water absorption/desorption tests, thickness swelling tests, density measurement, scanning electron microscopy, image analysis, contact angle, fiber length analysis and Fourier transform infrared spectroscopy was employed to understand the hygroscopic behavior of the recycled composites. Water absorption and thickness swelling behaviors were modeled using existing predictive models. Results indicated that generally the recycled composites had considerably lower water absorption and thickness swellings as compared with the original composites which were attributed to changes in physical and chemical properties of the composites induced by the recycling process.

Hybrid composites made from recycled materials: Moisture absorption and thickness swelling behavior

In this research, hybrid composite materials were made from the combination of recycled newspaper fiber (RNF) and poplar wood flour (PWF) as reinforcement, recycled polypropylene (RPP) as polymer matrix, and maleated polypropylene (MAPP) as coupling agent, by using injection molding. The effects of weight fractions of fibers and coupling agent concentration on the physical properties of the composites in terms of water absorption and thickness were studied. Composites containing more fraction of RNF exhibited maximum water absorption during the whole duration of immersion. This effect can be explained by the presence of a high amount of holocellulose present in the RNF, compared to the PWF. The addition of MAPP exhibited a beneficial effect on both the water absorption and thickness swelling by improving the quality of adhesion between polymer and fibers.

Water Absorption and Thickness Swelling Behavior of Polypropylene Reinforced with Hybrid Recycled Newspaper and Glass Fiber

This study aims to investigate the moisture absorption of recycled newspaper fiber and recycled newspaper-glass fiber hybrid reinforced polypropylene composites to study their suitability in outdoor applications. In this work composite materials were made from E-glass fiber (G), recycled newspaper (NP) and polypropylene (PP), by using internal mixing and hot-pressing molding. Long-term water absorption (WA) and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the WA and TS increase with NP content in composite and water immersion time before an equilibrium condition was reached. Composites made from the NP show comparable results as those made of the hybrid fiber. The results suggest that the water absorption and thickness swelling composite decrease with increasing glass fiber contents in hybrid fiber composite. It is interesting to find that the WA and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.

Water and Moisture Absorption and Thickness Swelling Behavior in Polypropylene/Wood Flour/Glass Fiber Hybrid Composites

The purpose of the current research was to investigate water/moisture absorption and associated thickness swelling and their rates in hybrid wood flour/E-glass fiber/propylene composite immersed in water, exposed to steam, and the influence of application of the glass fiber as well as maleic-anhydride-polypropylene (MAPP 2%) as coupling agent on those properties. The sample strips with 10 mm thickness and 70 mm width were made by using a laboratory twin-screw extruder. The specimens were immersed in water and exposed to steam for 4320 min to determine the water/moisture absorption and the thickness swelling as well as their rates in the composites. Results revealed that application of the glass fibers increased in the water/moisture absorption significantly in the hybrid composites due to formed micro-gaps in interfaces between wood flour and the glass fibers. However, application of the coupling agent (MAPP 2%) significantly reduced the micro-gaps and diminished the water/moisture absorption as well as the related thickness swelling in the hybrid composites.

Effect of Particle Size, Fiber Content and Compatibilizer on the Long-term Water Absorption and Thickness Swelling Behavior of Reed Flour/Polypropylene Composites

Reed (Phalaris sp.) flour was used to produce natural fiber polypropylene composites and effects of particle size, compatibilizer, and fiber content on the physical properties of the produced composites were evaluated. The particle sizes ranged from 40 mesh to smaller than 100 mesh sizes and fiber contents were 60% and 70% by weight. Composites were made through the extrusion process. Particle size proved to have very significant effects on both water absorption and thickness swelling of the composite formulations. The lowest water absorption and thickness swelling values were obtained at the lower fiber content and smallest particle size. Water diffusion coefficients were also smaller for smaller particle sizes and at lower fiber contents. The effect of compatibilzer was positive in terms of enhancing the dimensional stability of the composites. Composites containing the smallest particle size exhibited different water absorption and thickness swelling behaviors as seen in their considerably longer time required to reach maximum values.

The influence of wax-sizing on dimension stability and mechanical properties of bagasse particleboard

Bagasse particleboards (BPBs) were made using polymeric methylene diphenyl diisocyanate (pMDI) resin as binder and wax emulsion as dimension stabilizer. A factorial experiment was conducted to measure the effects of wax and pMDI resin content on particleboard dimension stability and mechanical properties. The data were compared with respective properties specified in the ANSI A208.1 standard for commercial M3 grade wood-based particleboard. Wax-sizing improved the linear expansion (LE) of the particleboards under both pMDI resin contents used in this research and all LE values were controlled under the critical value of 0.35%. The use of wax significantly reduced 24-h water absorption and thickness swelling compared to the control panels without wax. Wax-sizing at the moderate levels also showed positive influence on long-term water absorption and thickness swelling properties. Wax content levels, however, did not significantly influence water absorption and thickness swelling behavior. Wax-sizing had no evident negative effects on the bending properties of MDI-bonded bagasse particleboards under both resin contents, while it caused slightly negative effect on internal bond strength. Mechanical properties of all boards far exceeded the minimum values specified in ANSI A208.1 standard. The entire properties of the 5% pMDI BPBs were better than those of the 3% pMDI panels as expected.