Creep and recovery behavior of injection-molded isotactic polypropylene with controllable skin-core structure

Wang, Xin; Pan, Yamin; Qin, Yijing; Voigt, Monika; Liu, Xianhu; Zheng, Guoqiang; Chen, Qiang; Schubert, Dirk W.; Liu, Chuntai; Shen, Changyu

doi:10.1016/j.polymertesting.2018.05.040

Cited by 54 publications

(44 citation statements)

References 37 publications

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“…Isotactic polypropylene, iPP, is characterized by its relatively low manufacturing cost and its rather interesting properties, turning out as one of most versatile polymers actually produced at industrial level [1][2][3][4][5], both as a plastic and as a fiber. The use of metallocene catalysts constituted a great tool from mid 90s to synthesize under homogenous conditions polypropylenes with low amounts of oligomers and different tacticities [6] (atactic, isotactic or isoblock, among others), and also copolymers with ethylene, 1-butene and longer chain α-olefins [7][8][9][10][11][12] with high comonomeric molar fractions.…”

Section: Introductionmentioning

confidence: 99%

Hybrid materials obtained by in situ polymerization based on polypropylene and mesoporous SBA-15 silica particles: Catalytic aspects, crystalline details and mechanical behavior

Barranco‐García

Ferreira

Ribeiro

et al. 2018

Polymer

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Nanocomposites based on polypropylene have been prepared by in situ polymerization of propene in presence of mesoporous SBA-15 silica. Synthetic reactions were carried out with a zirconocene catalyst under either homogenous or supported conditions, the SBA-15 particles being used as carriers, and testing the immobilization of the catalytic system by several approaches. The existence of polypropylene able to crystallize within the mesoporous channels in the resulting materials is initially figured out from the appearance of a small endothermic process on heating calorimetric experiments, located at around 100 ºC. The presence of polypropylene crystallites confined within the SBA-15 mesostructure is thereafter confirmed by SAXS measurements through the intensity variation of the SBA-15 first order reflection, this change being dependent on composition. Accordingly, polypropylene chains can grow up either outside or inside the SBA-15 channels during polymerization and the mesoporous particles maintain their ordered hexagonal arrangement. Mechanical response, as deduced from indentation measurements, improves with SBA-15 incorporation (without varying the final processing temperature). Thus, stiffness increases and deformability is reduced in the nanocomposites as the SBA-15 content rises. Simultaneously, polypropylene amount within channels is enlarged. Amount of SBA-15 is, then, the most important variable.

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Section: Introductionmentioning

confidence: 99%

Hybrid materials obtained by in situ polymerization based on polypropylene and mesoporous SBA-15 silica particles: Catalytic aspects, crystalline details and mechanical behavior

Barranco‐García

Ferreira

Ribeiro

et al. 2018

Polymer

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“…Low density and high porosity polymer foam with controllable micro‐/nano‐structures could be formed through this simple and template‐free method. However, the obtained polymer foam usually has a skin structure, like some injection‐molded parts . This special structure will lead to the decline of the adsorption capacity and wetting properties.…”

Section: Methodsmentioning

confidence: 99%

Facile Thermally Impacted Water‐Induced Phase Separation Approach for the Fabrication of Skin‐Free Thermoplastic Polyurethane Foam and Its Recyclable Counterpart for Oil–Water Separation

Wang

Pan

Shen

et al. 2018

Macromol. Rapid Commun.

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Developing a facile large‐scale strategy to fabricate polymer foams with excellent wettability and recycling its counterpart for oil–water separation is in urgent demand. Here, a facile template‐free thermally impacted water‐induced phase separation approach for the fabrication of skin‐free thermoplastic polyurethane foam with a water contact angle of 147°, porosity more than 90%, density less than 14 mg cm−3, and excellent compressibility (>1000 cycles) is proposed. The foams show high efficiency of oil recovery (>98%) during the squeezing and pumping oil–water separation test. Moreover, the used foams could be recycled and reused to form refresh foams without sacrificing their high performance, which makes this method a promising prospect for environmental applications.

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“…On the one hand, this method is highly convenient, compared with other processing technologies such as fused deposition molding, 47,48 since injection molding can produce complex parts with high efficiency and special micro-structures. 49 Moreover, this method does not require complex equipment and can be nearly directly applied to practical production. On the other hand, the cellular structure can be adjusted to orient in a particular manner.…”

Section: Effect Of Cellular Orientation On Tensile Behaviormentioning

confidence: 99%

Combining foam injection molding with batch foaming to improve cell density and control cellular orientation via multiple gas dissolution and desorption processes

Zhou

Chen

2020

Polymers for Advanced Techs

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In contrast to solid parts fabricated through conventional injection molding (CIM), foamed parts manufactured via foam injection molding (FIM) exhibit substantial variations in mechanical properties, which are attributed to differences in the cellular structure. In this study, parts with different cellular structures are fabricated via FIM, during which the gas dissolution and desorption processes are controlled by subjecting the gas‐laden melt to reciprocating compression and expansion operations. The results suggest that the cell density can be drastically improved by rapidly decreasing the pressure caused by the mold opening and that the cell orientation obviously occurs in the direction perpendicular to the mold‐opening direction. Moreover, the cell density and cellular orientation can be adjusted by utilizing appropriate mold opening and closing operations, leading to improvements in the resultant ultimate mechanical properties. In particular, the foamed samples fabricated with controlled mold opening‐closing operations exhibit excellent tensile strength and strain‐at‐break, indicating that samples containing a high density of cells oriented along the tensile test direction facilitate the formation of superductility and an increase in tensile strength. Hence, a method that combines FIM with batch foaming has been proposed for improving the cellular structure and controlling the cellular orientation.

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Creep and recovery behavior of injection-molded isotactic polypropylene with controllable skin-core structure

Cited by 54 publications

References 37 publications

Hybrid materials obtained by in situ polymerization based on polypropylene and mesoporous SBA-15 silica particles: Catalytic aspects, crystalline details and mechanical behavior

Hybrid materials obtained by in situ polymerization based on polypropylene and mesoporous SBA-15 silica particles: Catalytic aspects, crystalline details and mechanical behavior

Facile Thermally Impacted Water‐Induced Phase Separation Approach for the Fabrication of Skin‐Free Thermoplastic Polyurethane Foam and Its Recyclable Counterpart for Oil–Water Separation

Combining foam injection molding with batch foaming to improve cell density and control cellular orientation via multiple gas dissolution and desorption processes

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