Conventional PP with a linear chain structure is not suitable for foam processing due to its poor rheological properties. In this study, PP was modified with PE through reactive melt blending of maleic anhydride-grafted PP (MA-PP) with a small amount of PE bearing glycidyl groups on its backbone (G-PE), with the aim of enhancing the melt rheological properties of PP to make it suitable for foam processing. An anhydride-epoxy reaction occurred between MA-PP and G-PE during the melt processing, resulting in the formation of a crosslinked polymer network, which was confirmed by FTIR spectroscopy, a solubility test, and the presence of a rubbery plateau above the melting point. Melt rheological tests demonstrated that the modified PP showed a pronounced shear-thinning effect and higher elasticity compared to pristine PP. Foaming tests using supercritical carbon dioxide as a foaming agent in an autoclave demonstrated that the modified PP could produce a microcellular foam with a closed-cell structure, which was not achievable with neat PP.
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http://dx.doi.org/10.3390/polym17010049 | DOI Listing |
Materials (Basel)
January 2025
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Silicon carbide-based titanium silicon carbide (SiC-TiSiC) composites with low free alloy content and varying TiSiC contents are fabricated by two-step reactive melt infiltration (RMI) thorough complete reactions between carbon and TiSi alloy in SiC-C preforms obtained. The densities of SiC-C preform are tailored by the carbon morphology and volumetric shrinkage of slurry during the gel-casting process, and pure composites with variable TiSiC volume contents are successfully fabricated with different carbon contents of the preforms. Due to the increased TiSiC content in the obtained composites, both electrical conductivity and electromagnetic interference (EMI) shielding effectiveness improved progressively, while skin depth exhibited decreased consistently.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Chemical Engineering, Hanyang University, Ansan 15588, Republic of Korea.
Conventional PP with a linear chain structure is not suitable for foam processing due to its poor rheological properties. In this study, PP was modified with PE through reactive melt blending of maleic anhydride-grafted PP (MA-PP) with a small amount of PE bearing glycidyl groups on its backbone (G-PE), with the aim of enhancing the melt rheological properties of PP to make it suitable for foam processing. An anhydride-epoxy reaction occurred between MA-PP and G-PE during the melt processing, resulting in the formation of a crosslinked polymer network, which was confirmed by FTIR spectroscopy, a solubility test, and the presence of a rubbery plateau above the melting point.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Mechanical Science and Engineering, The Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
Plant Cell Environ
January 2025
University of Kaiserslautern, Plant Physiology, Paul-Ehrlich-Str., Kaiserslautern, Germany.
Despite a high sucrose accumulation in its taproot vacuoles, sugar beet (Beta vulgaris subsp. vulgaris) is sensitive to freezing. Earlier, a taproot-specific accumulation of raffinose was shown to have beneficial effects on the freezing tolerance of the plant.
View Article and Find Full Text PDFACS Biomater Sci Eng
January 2025
CIRIMAT, Toulouse INP, Université Toulouse 3 Paul Sabatier, CNRS, Université de Toulouse, ENSIACET, 4 allée Emile Monso, Toulouse 31030, France.
Pyrophosphate-stabilized amorphous calcium carbonates (PyACC) are promising compounds for bone repair due to their ability to release calcium, carbonate, and phosphate ions following pyrophosphate hydrolysis. However, shaping these metastable and brittle materials using conventional methods remains a challenge, especially in the form of macroporous scaffolds, yet essential to promote cell colonization. To overcome these limitations, this article describes for the first time the design and multiscale characterization of freeze-cast alginate (Alg)-PyACC nanocomposite scaffolds.
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