Fabric Insert Injection Molding for the Preparation of Ultra-High Molecular Weight Polyethylene/High-Density Polyethylene Two-Component Self-Reinforced Composites

Abstract

The fabric insert injection molding approach can be applied to produce easily recyclable self-reinforced polymer composites (SrCs) whose reinforcement and matrix are from the same polymer. However, the mechanical properties of the SrCs are usually limited due to the poor impregnation of the inserted fabric. In this work, the ultra-high molecular weight polyethylene (UHMWPE) fabrics were used as the insert, and the high-density polyethylene (HDPE) melt was injected to fill the mold cavity and impregnate the fabrics. The UHMWPE/HDPE two-component SrCs were prepared. The large difference of melting temperatures between UHMWPE and HDPE can establish a wide processing temperature window, and thus the impregnation of the fabric can be improved by increasing temperature. The tensile strength and modulus of the UHMWPE/HDPE SrCs were up to 148 and 1132 MPa, respectively. The peel strength could be up to 35.2 N/cm. The influences of four main injection molding parameters, including the injection temperature, injection pressure/packing pressure, injection velocity, and packing time, were investigated. The temperature, pressure, viscosity, and density of the matrix in the mold cavity were calculated by the numerical simulation to indicate the impregnation process during the fabric insert injection molding process.

Driving sustainability in the automotive industry: bio-coated materials and modern strategies

“…Behind other advantages (e.g., interfacial bonding, price, and lightness), the use of self-reinforced composites means that the old products from these composites can be re-processed without any necessary separation techniques. The latest trend in the field of self-reinforced composites is the idea of the over-molding of fibers or fabrics directly in the cavity of the injection mold [99][100][101][102]. For example, Andrzejewski et al [103] overmolded self-reinforced poly (ethylene terephthalate) (PET) sheets with the same matrix polymer.…”

“…The achievements confirmed that the use of over-molding technology for the preparation of self-reinforced composites has the potential for commercial implementation, facilitating the recycling of materials. In other examples, Wang et al [101] used two layers of ultra-high molecular PE fabrics as inserts and high-density PE melt to fill the mold cavity and impregnate the fabrics, and Lee et al [102] proposed a 100% PP self-reinforced composite to produce a drone frame, where PP fiber was fabricated using spinning. Alternatively, Wis et al [105] prepared, also via over-molding, PLA onto PLA/jute-mat reinforced continuous fiber composite sheets.…”

“…This compound is not totally made from the same material but can be promising to produce biodegradable products suitable to be used in automotive, mainly under the hood and inner-trim applications [105]. However, the impregnation of polymer fiber fabrics is more difficult than that of usual fiber fabrics (e.g., glass, carbon, or natural) because the polymer fabric has a similar melting point with the polymer matrix and is easily molten at the processing temperature [101]. Nevertheless, monomaterial composites should be considered as a potential alternative in the new design of products, considering the easier and more sustainable end-of-life.…”

Plant Fibers as Composite Reinforcements for Biomedical Applications

“…In general, the principle of manufacturing by injection molding consists of heating and injecting the materials into a mold [91,92]. An advantage of injection molding over direct extrusion is that it results in materials with three-dimensional shapes for various industrial applications [110]. For instance, Jamadon et al carried out the synthesis of poly-lactic acid (PLA) reinforced with magnesium hydroxide (PLA/Mg(OH) 2 ) using the injection molding method to be applied in bone implants [111].…”

Development and Characterization of Supercooled Polyethylene Naphthalate

“…The difference in melting temperatures determines the processing window, and various techniques have been developed to expand this temperature range for SPC production. These methods include hot compaction of fibers or tapes [2][3][4][5][6][7], film stacking [8][9][10][11], a combination of hot compaction and film stacking [12], co-extrusion [13][14][15][16], extrusion-calendering [17,18], insert injection molding [19][20][21][22][23], and 3D printing [24,25].…”