scholarly journals Structural Characterization and Analysis of High-Strength Laminated Composites from Recycled Newspaper and HDPE

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1311 ◽  
Author(s):  
Binwei Zheng ◽  
Chuanshuang Hu ◽  
Litao Guan ◽  
Jin Gu ◽  
Huizhang Guo ◽  
...  

Recycled newspaper (NP) shows excellent potential as a reinforcement for polymer composites. Herein, high-strength laminated composites were prepared by using NP laminas as reinforcement and high-density polyethylene (HDPE) films as matrix. Physical and mechanical properties of the laminated composites were measured. It was found that the flexural strength of the composites had a good linear relationship to its density, with R2 = 0.9853. The flexural and tensile strength of the composites at the maximum density (1.40 g/cm3) reached up to 95.6 ± 2.4 MPa and 99.4 ± 0.8 MPa, respectively. SEM results showed that NP layer inside the composite became compact at the hot pressing time of 40 min, because the melted HDPE permeated into the NP layers to bond the NP fibers. Quantitative description of the composite porosity was conducted according to the density of the composite. The 24-h water absorption of the composite was highly related to its porosity, with R2 = 0.8994. This study reveals that density of laminated composites is an important parameter, which could be used to forecast the mechanical strength, and its derived value, porosity of the composites, could be used to predict the water absorption behavior of the composite.

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1166 ◽  
Author(s):  
Pavlo Bekhta ◽  
Ján Sedliačik

Thermoplastic films exhibit good potential to be used as adhesives for the production of veneer-based composites. This work presents the first effort to develop and evaluate composites based on alder veneers and high-density polyethylene (HDPE) film. The effects of hot-pressing temperature (140, 160, and 180 °C), hot-pressing pressure (0.8, 1.2, and 1.6 MPa), hot-pressing time (1, 2, 3, and 5 min), and type of adhesives on the physical and mechanical properties of alder plywood panels were investigated. The effects of these variables on the core-layer temperature during the hot pressing of multiplywood panels using various adhesives were also studied. Three types of adhesives were used: urea–formaldehyde (UF), phenol–formaldehyde (PF), and HDPE film. UF and PF adhesives were used for the comparison. The findings of this work indicate that formaldehyde-free HDPE film adhesive gave values of mechanical properties of alder plywood panels that are comparable to those obtained with traditional UF and PF adhesives, even though the adhesive dosage and pressing pressure were lower than when UF and PF adhesives were used. The obtained bonding strength values of HDPE-bonded alder plywood panels ranged from 0.74 to 2.38 MPa and met the European Standard EN 314-2 for Class 1 plywood. The optimum conditions for the bonding of HDPE plywood were 160 °C, 0.8 MPa, and 3 min.


2020 ◽  
Vol 10 (18) ◽  
pp. 6455
Author(s):  
Marianela Ripani ◽  
Hernán Xargay ◽  
Ignacio Iriarte ◽  
Kevin Bernardo ◽  
Antonio Caggiano ◽  
...  

High temperature effect on cement-based composites, such as concrete or mortars, represents one of the most important damaging process that may drastically affect the mechanical and durability characteristics of structures. In this paper, the results of an experimental campaign on cement mortars submitted to high temperatures are reported and discussed. Particularly, two mixtures (i.e., Normal (MNS) and High Strength Mortar (MHS)) having different water-to-binder ratios were designed and evaluated in order to investigate the incidence of both the mortar composition and the effects of thermal treatments on their physical and mechanical properties. Mortar specimens were thermally treated in an electrical furnace, being submitted to the action of temperatures ranging from 100 to 600 °C. After that and for each mortar quality and considered temperature, including the room temperature case of 20 °C, water absorption was measured by following a capillary water absorption test. Furthermore, uniaxial compression, splitting tensile and three-points bending tests were performed under residual conditions. A comparative analysis of the progressive damage caused by temperature on physical and mechanical properties of the considered mortars types is presented. On one hand, increasing temperatures produced increasing water absorption coefficients, evidencing the effect of thermal damages which may cause an increase in the mortars accessible porosity. However, under these circumstances, the internal porosity structure of lower w/b ratio mixtures results much more thermally-damaged than those of MNS. On the other hand, strengths suffered a progressive degradation due to temperature rises. While at low to medium temperatures, strength loss resulted similar for both mortar types, at higher temperature, MNS presented a relatively greater strength loss than that of MHS. The action of temperature also caused in all cases a decrease of Young’s Modulus and an increase in the strain corresponding to peak load. However, MHS showed a much more brittle behavior in comparison with that of MNS, for all temperature cases. Finally, the obtained results demonstrated that mortar quality cannot be neglected when the action of temperature is considered, being the final material performance dependent on the physical properties which, in turn, mainly depend on the mixture proportioning.


2021 ◽  
Vol 32 (3) ◽  
pp. 89-101
Author(s):  
Nur Nadia Nasir ◽  
◽  
Siti Amira Othman ◽  

Petroleum-based plastics have had a long history with varied materials and applications. However, the major drawback with these plastics is their harmful impact on the environment. Poor disposal management of these plastics have ultimately affected humans. Therefore, starch-based bioplastics have been widely used because of their renewability, sustainability and cost-effectiveness. This work investigated the effect of different concentrations of corn starch (10%, 15%, and 20% w/w of distilled water) and glycerol (20%, 30%, and 40% w/v of corn starch) on the properties of corn-based bioplastic films. Particularly, mechanical (tensile strength, Young’s modulus and elongation at break) and physical (water absorption rate and moisture content) properties were investigated. These films were prepared by the solvent casting method. It was demonstrated that the addition of 30% glycerol produced mechanical properties closest to the standard value, while films with a composition of 15% of corn starch had the most optimised value. Meanwhile, 20% glycerol and 20% corn starch produced a film with high strength and stiffness but lacked flexibility. Higher concentrations of starch and glycerol produced the highest moisture and water absorption rate. This was due to the highly hydrophilic nature of both corn starch and glycerol. However, the concentration of glycerol needs to be adjusted based on the intended use of the film. In conclusion, the concentration of corn starch and glycerol produced slightly different outcomes. Thus, the properties and application of the cornbased bioplastic films can be maximised by optimising the concentration of corn starch and glycerol.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiaosheng Liu ◽  
Weijun Wang ◽  
Quan Liu ◽  
Chao Yuan

The backfill of metal mines is easily damaged by the disturbance due to their low strength. We proposed a method that uses flexible meshes as the backfill skeleton to enhance the strength of the backfill. The physical and mechanical properties of the flexible mesh-reinforced filling body are investigated by combining theoretical analysis and laboratory experiments. The strengthening effect is remarkable with the flexible meshes. With the friction-passive resistance between the high-strength reinforcement material and the filling body, the insufficient tensile strength of the filling body is compensated and the reinforcement is improved. The ultimate compressive strength is increased by 1.07 to 1.35 times, and the elastic modulus is increased by 1.08 to 4.42 times. We concluded that the essence of strengthening the flexible mesh-reinforced filling is to increase the cohesive force of the filling and increase the ability to resist external load damage.


BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 789-804
Author(s):  
Qiang Jin ◽  
Lin Zhu ◽  
Jiedeerbieke Madiniyeti ◽  
Chunxia He ◽  
Li Li

Hydration-active steel slag and slag micropowder were used as inorganic fillers with silane coupling agent (KH550) to prepare wheat straw/polyvinyl chloride wood-plastic composites (WPCs) by extrusion molding. A 35-day immersion and a pre-immersion test were carried out to analyze the influence of steel slag and slag micropowder on the physical and mechanical properties of the WPCs under wet conditions. Results showed the following: (1) KH-550 exhibited a good surface modification effect on the activated steel slag and slag micropowder, (2) an increase in the activated steel slag and slag micropowder content could effectively reduce the percent water absorption of the WPCs by 20% to 25% and the expansion by 20% to 24%, respectively, compared with the control group, but had a limited effect on the tensile strength retention, and (3) pre-immersion could effectively induce the synergistic reinforcement effect of the active fillers, resulting in reaching the saturated water absorption within 20 days. The water absorption and tensile strength were respectively 18% to 25% lower and 1.5% to 3% higher than those of the composites without pre-immersion. The results of this study could provide experimental data and theoretical references for the influence of hydration-active inorganic fillers on WPC properties.


2016 ◽  
Vol 23 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Hakan Bolat ◽  
Pınar Erkus

AbstractConcrete is one of the materials in which polymer wastes are utilized. Generally, these wastes are added at specific rates in scientific studies but an important problem of waste polymers is size irregularity. Even when consistent dosage rates are used, variations in polymer size can lead to variability in the physical and mechanical properties of the concrete produced. The aim of this study is to determine physical and mechanical properties of polyvinyl chloride (PVC)-containing concretes. In order to produce normal and high strength concretes, 10%, 20%, and 30% replacement ratios of PVC powder and granules by volume of aggregate are used. Slump, fresh and hardened densities, compressive strength, capillary water absorption, and abrasion were tested on all concrete types. As the PVC ratio increases, important changes are seen in all physical and mechanical concrete properties. The unit weights of the 10%, 20%, and 30% replacement PVC powder concretes are lower by ∼4%, 8%, and 13%, respectively, as compared to the reference mixtures, and the replacement PVC granule concretes are lower by ∼2%, 4%, and 7%. Compressive strength test results showed similar trends. As PVC replacement increases, the capillary water absorption decreases between 10% and 50%, and abrasion decreases between 27% and 77%.


2013 ◽  
Vol 750-752 ◽  
pp. 38-42
Author(s):  
Wang Wang Yu ◽  
Juan Li ◽  
Yun Ping Cao

In this study, the silvergrass (SV) was used to reinforce HDPE composites. The effects of polymeric methylene diphenyl diisocyanate (PMDI) content, slivergrass fibers content on the mechanical, water absortion of wood plastic composites (WPCs) were investigated. It was found that the mechanical properties of the SV reinforced HDPE composites can be improved by PMDI treatment. The highest tensile strength and flexural strength of the composites can be reached with 50% SV contents at the SV: PMDI=6:1. It has been proved that the hydroxyl groups of SV fibers which can react with the-NCO by FTIR. It also can be concluded that the water absorption of PMDI treated WPCs was lower than untreated ones.


1970 ◽  
Vol 43 (4) ◽  
pp. 581-587
Author(s):  
M Hasan Shahria ◽  
M Ashaduzzaman ◽  
M Iftekhar Shams ◽  
Arifa Sharmin ◽  
M Muktarul Islam

The study was conducted to find out the potentiality of Pitali (Trewia nudiflora) for manufacturing commercial plywood and evaluating its physical and mechanical properties. Two 9-ply plywood of 2.4m x 1.2m x 18mm size were manufactured using liquid urea formaldehyde adhesive. The physical and mechanical properties of T. nudiflora plywood were compared with the existing market available plywood manufactured by Simul (Bombax ceiba). It was found that density were 509.82 kg/m3 and 490.96 kg/m3, moisture content after curing were 10.67% and 17.61%, thickness swelling were 6.90% and 7.29%, linear expansion were 0.19% and 0.15%, water absorption were 50.89% and 64.79%, MOR were 29.94 N/mm2 and 27.05 N/mm2, MOE were 1613.89 N/mm2 and 1160.68 N/mm2, and tensile strength were 14.75 N/mm2 and 13.12 N/mm2 for T. nudiflora plywood and market plywood respectively. The evaluated physical and mechanical properties of T. nudiflora plywood were also compared with some relevant results and standards reported earlier. Key Words: Plywood, Trewia nudiflora, Physical properties, Mechanical properties. doi: 10.3329/bjsir.v43i4.2249 Bangladesh J. Sci. Ind. Res. 43(4),581-587, 2008


2020 ◽  
Vol 7 (3) ◽  
pp. 156-175
Author(s):  
Tavga Mohammad ◽  
◽  
Azad Mohammed

In this research, physical and mechanical properties of high strength concrete containing PVC waste have been investigated. The fine aggregate was replaced with PVC waste with two different gradings (fine grading and coarse grading) at dosages of 0%, 5%, 10%, 20%, and 40% by the volume of aggregate. The properties include physical properties of density and water absorption, mechanical properties of compressive strength, splitting tensile strength and flexural strength. Results show that in general, using 5% PVC replacement in high strength concrete has no appreciable effect to damage the physical and mechanical properties of concrete. With increasing PVC aggregate content, the deterioration of the concrete properties was observed. The coarse graded PVC aggregate has some more effect on the deterioration of concrete properties compared to the fine graded PVC aggregate.


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