Pushing the Boundaries of Starch Foams: Novel Laminar Composites with Paper Reinforcement

This work explores the development of biodegradable laminar composite foams for cushioning applications.The focus lies on overcoming the inherent brittleness of starch foams by incorporating various paper types as rein-forcement.Tapioca starch and glutinous starch were blended in varying ratios(100:0–0:100)to optimize the base material’s properties.The morphology,density,flexural strength,and impact strength of these starch blends were evaluated.The results revealed a trade-off between impact strength and density,with increasing glutinous starch content favoring impact resistance but also leading to higher density.The optimal ratio of tapioca to glutinous starch for achieving maximumflexural strength and modulus was determined to be 60:40.Theflexural strength of the composite material at this ratio reached a peak value of 5.3±0.6 MPa,significantly surpassing theflexural strength of pure tapioca foam,which was measured to be 3.5±0.4 MPa.Building on this foundation,novel lami-nar composite foams were fabricated using the 60:40 starch blend reinforced with mulberry paper,kraft paper,and newsprint paper.To enhance the interfacial adhesion between the starch matrix and paper reinforcement,a silane coupling agent was employed at a 10 wt%loading on the paper.The incorporation of paper reinforcement into starch foams was found to enhance their mechanical properties.Specifically,flexural strength values increased from 5.3±0.6 MPa for the unreinforced starch foam to 6.8±0.6 MPa,8.1±0.9 MPa,and 7.4±0.1 MPa when reinforced with mulberry paper,kraft paper,and newsprint paper,respectively.Notably,kraft paper reinforcement led to the most enhancements inflexural strength,flexural modulus,and impact strength.This research paves the way for developing sustainable cushioning materials with competitive mechanical properties using bio-based resources like starch and paper.

B2-CuZr reinforced amorphous alloy matrix composites:A review

B2-CuZr phase reinforced amorphous alloy matrix composites has become one of the research hotspots in the field of materials science due to the“transformation-induced plasticity”phenomenon,which makes the composites show better macroscopic plastic deformability and obvious work-hardening behavior compared to the conventional amorphous alloy matrix composites reinforced with ductile phases.However,the in-situ metastable B2-CuZr phase tends to undergo eutectoid decomposition during solidification,and the volume fraction,size,and distribution of B2-CuZr phase are difficult to control,which limits the development and application of these materials.To date,much efforts have been made to solve the above problems through composition optimization,casting parameter tailoring,and post-processing technique.In this study,a review was given based on relevant studies,focusing on the predictive approach,reinforcing mechanism,and microstructure tailoring methods of B2-CuZr phase reinforced amorphous alloy matrix composites.The research focus and future prospects were also given for the future development of the present composite system.

Effects of two modification methods on the mechanical properties of wood flour/recycled plastic blends composites: addition of thermoplastic elastomer SEBS-g-MAH and in-situ grafting MAH

The effect of maleic anhydride grafted styrene-ethylene- buty-lene-styrene block copolymer （SEBS-g-MAH） and in-situ grafting MAH on mechanical, dynamic mechanical properties of wood flour/recycled plastic blends composites was investigated. Recycled plastic polypro-pylene （PP）, high-density polyethylene （HDPE） and polystyrene （PS）, were mixed with wood flour in a high speed blender and then extruded by a twin/single screw tandem extruder system to form wood flour/recycled plastic blends composites. Results show that the impact properties of the composites were improved more significantly by using SEBS-g-MAH compatibilizer than by using the mixtures of MAH and DCP via reactive blending in situ. However, contrary results were ob-served on the tensile and flexural properties of the corresponding com-posites. In General, the mechanical properties of composites made from recycled plastic blends were inferior to those made from virgin plastic blends, especially in elongation break. The morphological study verified that the interfacial adhesion or the compatibility of plastic blends with wood flour was improved by adding SEBS-g-MAH or in-situ grafting MAH. A better interfacial bonding between PP, HDPE, PS and wood flour was obtained by in-situ grafting MAH than the addition of SEBS-g-MAH. In-situ grafting MAH can be considered as a potential way of increasing the interfacial compatibility between plastic blends and wood flour. The storage modulus and damping factor of composites were also characterized through dynamic mechanical analysis （DMA）.

Study on plant fiber/plastic composites as the substrate of floorboard

Three kinds of composites （fiber/Polypropylene, fiber/Polyethelene, and fiber/Polystyrene） were made by using hot pressing process for substrate of floorboard and the properties of each kind of composites were tested. MORs of PP/wood fiber, PS/fiber, and PE/fiber composites with coupling agent added were raised by 18.4%, 37.1%, and 42%. respectively, compared to those without coupling agent. Among the three kinds of fiber/plastic composites, fiber/PP composite has best mechanical properties, and it can meet quality standard of eligible grade product and come up to the excellent grade products of China when the coupling agent is added. The performance of composite made of PE/fiber or PS/fiber can exceed qualified product grade only with coupling agent added.

Properties of paper mill sludge–wood fiber–HDPE composites after exposure to xenon-arc weathering

We used paper mill sludge（PMS） to substitute for part of the wood fibers（WF） used to reinforce high density polyethylene（HDPE）.The resulting composites were subjected to xenon-arc weathering.The composite filled with limited PMS（under 10 %） had mechanical properties and aging resistance similar to those without PMS.The composites containing more PMS faded and cracked more readily than those without PMS.Based on the carbonyl index,crystallinity,and wood index,PMS appeared to accelerate the degradation of composites during weathering.Adding PMS to WF–HDPE composites reduced the weathering resistance,and this reduction was not significant if the PMS content did not exceed 20 % of the wood fibers.Therefore,PMS could be used as a reinforcement in wood-plastic composites at levels less than20 % of the wood fiber content.

Production of mahogany sawdust reinforced LDPE wood–plastic composites using statistical response surface methodology

We produced wood–plastic composite board by using sawmill wastage of mahogany（Swietenia macrophylla） wood and low density polyethylene.We used multi-response optimization to optimize the process parameters of composite board production including mixing ratio,fire retardant（%） and pressing time（min）.We investigated the effects of these three process parameters in the mechanical and physical properties of the composite board.Afterwards,Box–Behnken design was performed as response surface methodology with desirability functions to attain the optimal level of mixing ratio,fire retardant and pressing time（min）.The maximum modulus of elasticity（MOE） and modulus of rupture（MOR） were achieved at the optimal conditions of wood plastic mixing ratio of60：40,pressing time of 9 min and zero fire retardant percentage.The optimized MOR and MOE were 13.12 and1,781.0 N mm-2,respectively.

Novel wood-plastic composite fabricated via modified steel slag:Preparation,mechanical and flammability properties

A novel method was developed to enhance the utilization rate of steel slag(SS).Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane(KH550),we obtained modified SS(MSS),which was used to prepare MSS/wood-plastic composites(MSS/WPCs)by replacing talcum powder(TP).The composites were fabricated through melting blending and hot pressing.Their mechanical and combustion properties,which comprise heat release,smoke release,and thermal stability,were systematically investigated.MSS can improve the mechanical strength of the composites through grafting reactions between wood powder and thermoplastics.Notably,MSS/WPC#50(16wt%MSS)with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive performance.Compared with those of WPC#0 without MSS,the tensile,flexural,and impact strengths of MSS/WPC#50 were increased by 18.5%,12.8%,and 18.0%,respectively.Moreover,the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%,the highest vertical burning rating at the V-1 level,and the lowest horizontal burning rate at 44.2 mm/min.The formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#50.However,the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties,possibly due to the weak grafting caused by SS powder agglomeration.These findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

On the homogenization of metal matrix composites using strain gradient plasticity

The homogenized response of metal matrix composites（MMC） is studied using strain gradient plasticity.The material model employed is a rate independent formulation of energetic strain gradient plasticity at the micro scale and conventional rate independent plasticity at the macro scale. Free energy inside the micro structure is included due to the elastic strains and plastic strain gradients. A unit cell containing a circular elastic fiber is analyzed under macroscopic simple shear in addition to transverse and longitudinal loading. The analyses are carried out under generalized plane strain condition. Micro-macro homogenization is performed observing the Hill-Mandel energy condition,and overall loading is considered such that the homogenized higher order terms vanish. The results highlight the intrinsic size-effects as well as the effect of fiber volume fraction on the overall response curves, plastic strain distributions and homogenized yield surfaces under different loading conditions. It is concluded that composites with smaller reinforcement size have larger initial yield surfaces and furthermore,they exhibit more kinematic hardening.

Filling Behavior of Wood Plastic Composites

WPC （wood plastic composites） are a young generation of composites with rapidly growing usage within the plastics industry. The advantages are the availability and low price of the wood particles, the possibility of partially substituting the polymer in the mixture and sustainable use of the earth＇s resources. The current WPC products on the market are to a large extent limited to extruded products. Nowadays, there is a great interest in the market for consumer products in more use of WPC as an alternative to pure thermoplastics in injection molding processes. This work presents the results of numerical simulation and experimental visualization of the mold filling process in injection molding of WPC. The 3D injection molding simulations were done with the commercial software package Autodesk~ Moldflow Insight 2016 （AMI）. The mold filling experiments were conducted with a box-shaped test part. In contrast to unfilled polymers, the WPC has reduced melt elasticity so that the fountain flow often does not develop. This results in irregular flow front shapes in the molded part, especially at high filler content.

Preparation of Polyimide Fiber/Thermoplastic Resin Composites with Improved Mechanical Properties

As a high-performance material for preparing composite materials, polyimide fibers suffer from many potential drawbacks, including poor bonding with other substrates, which results in composite materials with poor mechanical properties. Therefore, this study proposed a simple and rapid technique for obtaining loose, porous polyimide fiber papers by implementing a wet method using equal amounts of polyimide fiber and polyimide fiber paper as reinforcements, respectively. The polyimide resin-based composite materials were prepared by hand lay-up and hot pressing. The results showed that the paper-based reinforcement exhibited high porosity and the fibers were arranged with a uniform pore size distribution. The tensile properties, bending performance, and interlaminar shear performance of the paper-based composite improved by 130%, 108%, and 34.5%, respectively, compared to those of the fiberbased counterpart. The factors affecting the mechanical properties of the composites were analyzed based on the fiber length, fiber beating or lack thereof, and the basis weight of the paper. The increased uniformity of the polyimide fiber paper changed the ordering of the fibers and resolved drawbacks such as difficult dispersion, uneven pore size distribution, and poor mechanical properties related to single fibers in the resin-based composite material.

Impact Wear Properties of Metal-Plastic Multilayer Composites Filled with Glass Fiber Treated with Rare Earth Element Surface Modifier

The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigated. Experimental results show that the metal-plastic multilayer composite filled with glass fiber exhibits excellent friction and impact wear properties when using rare earth elements as surface modifier for the surface treatment of glass fiber.

Preliminary study of the effects of EVA coupling agents on properties of wood-plastic composites

As a hot-melt adhesive, ethylene-vinyl-acetate （EVA） has been used in many industrial applications. But studies of the application of EVA in wood-plastic composites （WPC） are relatively few, so we have investigated the proposition of whether EVA is a suitable coupling agent for WPC or not. The results show that EVA with 8% VA is not a suitable coupling agent, because it reduces the mechanical properties of WPC without any significant effect on its physical properties. With an increase in the amount of wood powder, the mechanical properties of WPC decrease and the ability of water absorption of WPC increases.

Effect of Rare Earths-Treated Glass Fiber on Impact Wear-Resistance of Metal-Plastic Multilayer Composites

The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.

Mechanical properties of wood flour/recycled-thermoplastic-blends composites

The mechanical properties of composites prepared from wood flour and thermoplastic blends were investigated. Thermoplastic mixtures of polypropylene (PP) and high-density polyethylene (HDPE) and polystyrene (PS), virgin or recycled, were mixed with wood flour in a high speed blender and then extruded by a specially designed twin/single screw extruder system to form wood-flour/thermoplastic-blends composites (WTBCs). Comparative studies were made to evaluate the effectiveness of the two modification methods of the thermoplastic blends, the one of the addition of maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer (SEBS-g-MAH) as compatibilizer and the other of blend grafting of maleic anhydride (MAH) using dicumyl peroxide (DCP) as initiator by reactive extrusion. The results showed that the impact properties of WTBCs using SEBS-g-MAH as compatilizer were better improved than that of the blend grafting. However, adverse results were observed on the tensile and flexural properties of the corresponding WTBCs. The mechanical properties of WTBCs prepared from recycled plastic blends were poorer to some extent than that from virgin plastic blends in general, especially in elongation break. The morphology of WTBCs breaking section was analyzed by scanning electron microscopy (SEM) and the results showed that a good interfacial adhesion between wood flour and polymer matrix was observed with both of the two modification methods. However, by blend grafting of adding DCP as initiator and MAH as monomer, a better interfacial bonding between wood and plastic matrix was obtained than that of the addition of SEBS-g-MAH. Blend grafting can be considered as a potential way of increasing the interfacial compatibility of different plastics and between plastic blends and wood.

THE MEASUREMENT OF SLIGHT WEAR OF ENGINEERING PLASTIC COMPOSITES USING NEUTRON ACTIVATION ANALYSIS

In this paper, an experimental method was described for measuring very slight wear of polymer by using neutron activation analysis (NAA). By means of adopting appropriate neutron flux suitable experimental parameters and measuring technique, the method was performed under the condition without any effect upon the mechanical properties of wearing. The sensitivity of the wear measurements reached the order of magnitude of 10-7g for engineering plastics containing about 1 wt% of zinc. The comparison could be made rapidly between different materials with different resistance to wear. The results were free from the influence of vibration of test systems, elastic deformation of materials, media and moisture absorption, and etc. Combined with autoradiograph, the present technique can be used to investigate the backtransfer of ground debris of metallic fillers from the counter part to the specimen. A multifunctional plane wear testing machine was set up for obtaining wear data and friction coefficient. The present work provides a new, rapid and sensitive measuring technique and also a screening method for the wear of polymers.

Effect of plastic deformation on microstructure and hardness of AlSi/Al gradient composites

The effects of plastic deformation on the evolution of microstructure and micro-hardness were studied on plates made from a cylindrical ingot of AlSi/Al aluminum composite. This ingot was produced by double-stream-pouring continuous casting(DSPCC). The results show that the three layers, i.e. the external pure aluminum, internal Al-Si alloy and the transition gradient layer, are maintained after compression as well as rolling processing. With the decrease in thickness of the gradient composite plate, the fluctuation of micro-hardness in transition layer in the direction normal to the applied force is significantly reduced. A simplified lamination model was used to evaluate qualitatively the micro-hardness distribution in the direction parallel to the applied force. However, the model is invalid in the explanation of the fluctuation of the micro-hardness in the direction normal to the applied force. The micro-hardness distribution variation in this direction is mainly attributed to the deformation of α(Al) matrix incorporated the dissolution and spheroidization of eutectic silicon phase.

EFFECTS OF MICROSTRUCTURE ON THE MACROSCOPIC ELASTO-PLASTIC PROPERTIES OF METAL MATRIX COMPOSITES

The generalized self-consistent finite-element iterative averaging method was adopted to analyze the elasto-plastic tensile properties of SiC whiskers reinforced aluminum matrix composites. The effects of varying fiber's aspect ratio and volume fraction on the macroscopic elasto-plastic deformation of the composites were studied. By the analysis of microscopic stress fields, the relation between the propagation of the elasto-plastic region in the matrix and the macroscopic elasto-plastic deformation of composites was discussed. It was found that the propagation of the plastic region in the matrix between the fiber's ends would affect prominently the elasto-plastic tensile behaviour of the composites. It was shown that the characterization of the stress-strain response in terms of the 0.2% offset yield strength is incomplete.

Review of Agro Waste Plastic Composites Production

This article reviews the literature reports base on agro waste plastic composites using different fiber as fillers and reinforcements. Various processing methods and conditions;compression molding process, injection molding, and extrusion method are used in the composites productions. Characterization challenges associated with the agro waste plastic composites productions were also examined. Thus, the findings of this research review can be use as a data base for further inquiring into the agro waste plastic composites in a view to enhance the development of the sector.

Chemicals Used in Polymeric Material Coated Waste Paper Composites

In this research, at different quantities as fillers, Boric Acid, Calcite (CaCO3), SPT (Sodium Perborate Tetrahydrate) and as coupling matters, 3%, MAPE (Maleic Anhydride Grafted Polyethylene), Titanate and Silanyl (Vinyltriethoxysilane) were added waste paper. Composite boards were pressed and cut in 1 × 30 × 30 cm. In order to identify some properties of the produced boards, experimental works were applied according to the standards. In conclusion, bending stress reduced with filler materials and chemicals was reduced even more than the bending stress except for some experimental groups. In addition, it was observed that the coupling chemicals increased the bending strength and modulus of elasticity compared to the fillers.

A Simulation Software for the Prediction of Thermal and Mechanical Properties of Wood Plastic Composites

Modelling and simulation has become an important tool in research and development. Simulation models are used to develop better understanding of the internal properties and impact of various parameters on the final quality of the product or process. Simulation model reduces the number of experiments and saves the wastage of material, time and money and are widely used in automobile industry, aircrafts manufacturing, process engineering, training for military, health care sector and many more. Wood Plastic Composite （WPC） is a bio-composite made by mixing wood fibers and plastic granules together at high temperature by compression molding or injection molding. A large quantity of WPC is rejected due to poor quality and low mechanical strength. There is a need to improve the understanding of the wood plastic composites, with both theoretical and experimental analysis. The impact of various parameters and processing conditions on the final product is not known to the industry people, due to less simulation models in this field. A new simulation software WPC Soft is developed to predict the mechanical and thermal properties of WPC. The software can predict the mechanical and thermal properties of WPC. The simulation results were validated with the experimental results and it was observed that the predicted values are quite close to the experimental values and with the further refining of the model, prediction can be further improved. The present simulation software can be easily used by the industry people and it requires very little knowledge of computers or modeling for its operation.