scholarly journals Water Absorption and Hygrothermal Aging Behavior of Wood-Polypropylene Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 782 ◽  
Author(s):  
Wei Wang ◽  
Xiaomin Guo ◽  
Defang Zhao ◽  
Liu Liu ◽  
Ruiyun Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Natural Fiber ◽  
Glass Fibers ◽  
Diffusion Constant ◽  
Water Molecules ◽  
Wood Powder ◽  
Polypropylene Composites ◽  
Effect Of Water ◽  
Composite Samples

Environmentally sound composites reinforced with natural fibers or particles interest many researchers and engineers due to their great potential to substitute the traditional composites reinforced with glass fibers. However, the sensitivity of natural fiber-reinforced composites to water has limited their applications. In this paper, wood powder-reinforced polypropylene composites (WPCs) with various wood content were prepared and subjected to water absorption tests to study the water absorption procedure and the effect of water absorbed in the specimens on the mechanical properties. Water soaking tests were carried out by immersion of composite specimens in a container of distilled water maintained at three different temperatures, 23, 60 and 80 °C. The results showed that the moisture absorption content was related to wood powder percentage and they had a positive relationship. The transfer process of water molecules in the sample was found to follow the Fickian model and the diffusion constant increased with elevated water temperature. In addition, tensile and bending tests of both dry and wet composite samples were conducted and the results indicated that water absorbed in composite specimens degraded their mechanical properties. The tensile strength and modulus of the composites reinforced with 15, 30, 45 wt % wood powder decreased by 5.79%, 17.2%, 32.06% and 25.31%, 33.6%, 47.3% respectively, compared with their corresponding dry specimens. The flexural strength and modulus of the composite samples exhibited a similar result. Furthermore, dynamic mechanical analysis (DMA) also confirmed that the detrimental effect of water molecules on the composite specimens.

Effect of water absorption on the mechanical properties of bamboo/glass-reinforced polybenzoxazine hybrid composite

2020 ◽  
Vol 29 (1) ◽  
pp. 3-14
Author(s):  
Kai Zhang ◽  
Wenyan Liang ◽  
Fangxin Wang ◽  
Zhenqing Wang
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Natural Fiber ◽  
Glass Fibers ◽  
Water Immersion ◽  
Mechanical Tests ◽  
Sem Images ◽  
Pressing Method ◽  
Effect Of Water ◽  
The Matrix

In this study, bamboo and glass fibers were successfully added into bisphenol A–aniline-based benzoxazine resin by hot pressing method. The effect of water absorption on the mechanical properties of the neat benzoxazine and its composites was studied. The composites prepared in this study has been proved to exhibit better water resistance than some conventional natural fiber/polymer composites due to good hydrophobicity of the benzoxazine matrix. From the mechanical tests, the tensile performance of both neat benzoxazine and the composites degraded seriously after prolonged immersion in water. However, neat benzoxazine and the composites maintained relatively higher residual flexural properties (residual mechanical properties refer to the ratio of strength and modulus of the saturated samples to that of the nonaged samples) after 20 days of water immersion. The effect of water molecules on the fracture surface morphologies of the composites was studied using a scanning electron microscope (SEM). The SEM images showed that the interfacial bonding between fibers and the matrix degraded seriously due to the attack of water.

Mechanical Properties of Structural Paper-Polypropylene Composite Laminates

2015 ◽  
Vol 825-826 ◽  
pp. 11-18 ◽  
Author(s):  
Martina Prambauer ◽  
Christian Paulik ◽  
Christoph Burgstaller
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Natural Fiber ◽  
Glass Fibers ◽  
Cellulose Fiber ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Polypropylene Composites ◽  
Flexural Testing

Natural fiber reinforced polymers have gained increasing interest in research with the aim of replacing conventional reinforcements, such synthetic or glass fibers. In this work, whole paper sheets of copy, filter and newspaper were used for fabricating cellulose fiber reinforced polypropylene composites with MAPP as a coupling agent. By varying the amount and type of paper, the influence of these parameters on the mechanical properties was observed. The laminates were produced by a film hand stacking method and hot pressing. The characterization was carried out by tensile and flexural testing. Remarkable results were obtained for copy and newspaper composites at a fiber content of 30 and 40 vol.-%. In summary, structural paper reinforced composites with attractive mechanical properties were obtained, indicating the high potential of whole paper sheets as polymer reinforcement.

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

scholarly journals Effect of Water on Some Mechanical Properties for Sawdust and Chopped Reeds /UPE composites

2011 ◽  
Vol 8 (2) ◽  
pp. 551-560
Author(s):  
Baghdad Science Journal
Keyword(s):  
Mechanical Properties ◽  
Weight Gain ◽  
Flexural Strength ◽  
Young’S Modulus ◽  
Polyester Resin ◽  
Young's Modulus ◽  
Unsaturated Polyester ◽  
Molding Method ◽  
Effect Of Water ◽  
Composite Samples

In this study, composite materials were prepared using unsaturated polyester resin as binder with two types of fillers (sawdust and chopped reeds). The molding method is used to prepare sheets of UPE / sawdust composite and UPE / chopped reeds composite. The mechanical properties were studied including flexural strength and Young's modulus for the samples at normal conditions (N.C). The Commercial wood, UPE and its composite samples were immersed in water for about 30 days to find the weight gain (Mt%) of water for the samples, also to find the effect of water on their flexural strength and Young's modulus. The results showed that the samples of UPE / chopped reeds composite gained highest values of flexural strength (24.5 MPa) and Young's modulus (5.1 GPa) as compared with other composites at (N.C). The results showed that the wet samples of sawdust composite have lowest values of weight gain (Mt %) of water (0.043%) as compared with other composites after immersion. Also it’s showed a slight decrease in values of Young's modulus for all the samples after immersion as compared with the samples at (N.C). Finally it’s showed a slight decrease in values of flexural strength for all the samples except for the composite material formed from UPE / chopped reeds which showed an increase in the value of flexural strength after immersion, where the wet samples of UPE / chopped reeds composite gained (29 MPa) as compared with the samples at (N.C).

scholarly journals Effects of High-Temperature Exposure on the Mechanical Properties of Kenaf Composites

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1643 ◽  
Author(s):  
Nabilah Afiqah Mohd Radzuan ◽  
Dulina Tholibon ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Che Hassan Che Haron
Keyword(s):  
Mechanical Properties ◽  
Natural Fiber ◽  
Molding Process ◽  
Kenaf Fiber ◽  
Polypropylene Composites ◽  
Safety Issues ◽  
Automotive Parts ◽  
Kenaf Composites ◽  
Temperature Exposure ◽  
Kenaf Fibers

Automotive parts, including dashboards and trunk covers, are now fabricated through a compression-molding process in order to produce lightweight products and optimize fuel consumption. However, their mechanical strength is not compromised to avoid safety issues. Therefore, this study investigates kenaf-fiber-reinforced polypropylene composites using a simple combing approach to unidirectionally align kenaf fibers at 0°. The kenaf composite was found to withstand a maximal temperature of 120 °C. The tensile and flexural strengths of the aligned kenaf composites (50 and 90 MPa, respectively) were three times higher than those of the commercialized Product T (between 39 and 30.5 MPa, respectively) at a temperature range of 90 to 120 °C. These findings clearly showed that the mechanical properties of aligned kenaf fibers fabricated through the combing technique were able to withstand high operating temperatures (120 °C), and could be used as an alternative to other commercial natural-fiber products.

Mechanical and Morphological Properties of Sisal/Glass Fiber-Polypropylene Composites

2008 ◽  
Vol 47-50 ◽  
pp. 486-489 ◽  
Author(s):  
Kasama Jarukumjorn ◽  
Nitinat Suppakarn ◽  
Jongrak Kluengsamrong
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Weight Ratio ◽  
Morphological Properties ◽  
Fiber Reinforced ◽  
Polypropylene Composites ◽  
Specific Strength ◽  
Fiber Reinforced Polymer Composites

Natural fiber reinforced polymer composites became more attractive due to their light weight, high specific strength, biodegradability. However, some limitations e.g. low modulus, poor moisture resistance were reported. The mechanical properties of natural fiber reinforced composites can be improved by hybridization with synthetic fibers such as glass fiber. In this research, mechanical properties of short sisal-PP composites and short sisal/glass fiber hybrid composites were studied. Polypropylene grafted with maleic anhydride (PP-g-MA) was used as a compatibilizer to enhance the compatibility between the fibers and polypropylene. Effect of weight ratio of sisal and glass fiber at 30 % by weight on the mechanical properties of the composites was investigated. Morphology of fracture surface of each composite was also observed.

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