In-line Plasma-induced Graft-copolymerization of Pentaerythritol Triacrylate onto Polypropylene

Highly Enhancing Electrical, Thermal, and Mechanical Properties of Polypropylene/Graphite Intercalation Compound Composites by In Situ Expansion during Melt Mixing

Polypropylene/graphite intercalation compound (PP/GIC) composites are prepared via melt mixing at three different temperatures (180, 200, and 220 °C). The dispersion of GICs in the composites is clearly improved due to the increased interlamellar spacing caused by in situ expansion of GICs at higher temperatures, which facilitates the intercalation of PP molecular chains into the GIC galleries. As a result, the PP/GIC composite with 10 wt% GICs prepared at 220 °C (PG220) presents a dielectric constant of about 1.3 × 10⁸ at 10³ Hz, which is about six orders higher than that of the composite prepared at 180 °C (PG180). Moreover, the thermal conductivity of the PG220 sample (0.63 Wm^-1K^-1) is 61.5% higher than that of the PG180 sample. The well-dispersed GICs accelerates the crystallization of PP by increasing the nucleation point and enhances the thermal stability of the composites. The PG220 sample shows a Young's modulus that is about 21.2% higher than that of the PG180 samples. The results provide an efficient approach for fabricating polymer/GIC composites without complex exfoliation and dispersion processes.

Crystallization, Mechanical, and Antimicrobial Properties of Diallyl Cyanuric Derivative-Grafted Polypropylene

A functional N-halamine precursor with double bonds, 1-3-diallyl-s-triazine-2,4,6-trione (DTT), was synthesized and grafted onto polypropylene using dicumyl peroxide (DCP) as an initiator via melt blending at 200 °C. The DTT content grafted onto the polypropylene (PP) backbone was depended on both DTT and DCP concentrations in feed. The crystallization temperature of PP increased from 116 °C (neat PP) to 123 °C (10% DTT) with the increasing DTT content. Meanwhile, the crystallization rate and relative crystallinity of PP were significantly increased after introduction of the N-halamine precursor. Moreover, the incorporation of DTT had partial compensation for the decreasing mechanical properties of polypropylene, which resulted from degradation. When the amount of added DTT reached up to 5%, the chlorinated DTT-modified PP sheets were able to kill 105-6 cfu/mL Escherichia coli (CMCC 44103) and Staphylococcus aureus (ATCC 6538) within 10 min. The DTT-modified PP with the regenerating antibacterial property may have great potential for application in packaging, filters, and hygienic products.

A direct functionalization of polyolefins for blend compatibilization by an insertion of 1,1-bis(phenylsulfonyl)ethylene (BPSE)

A mild post-modification of polyethylene (PE) & polypropylene (PP) to insert phenylsulfonyl groups is reported, the modified samples demonstrated to act as blend compatibilizers.