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[This corrects the article DOI: 10.1371/journal.pone.0278290.].

Abstract Polyhedral oligomeric silsesquioxane (POSS) is commonly used to lower the dielectric constant of polyimide (PI), but the toughness generally deteriorates. In this paper, trifluoropropyl POSS (FPOSS) is surprisingly found [...]

Liquid crystal polymers (LCPs) should be widely used as substrates in flexible copper clad laminate (FCCL) owing to their unique advantages. However, the poor adhesion of LCPs to copper foils hinders their applications. Considering the good adhesion between polyimides and copper foils, imide groups have previously been introduced into the main chains of LCP molecules. In the present paper, to further enhance the adhesion of the LCPEIs, the 1‐hydroxy‐7‐azabenzotriazole (HOAt) is used to terminate the main chains of LCPEI molecules, which arises from the excellent coordination interaction between the azabenzotriazole groups and copper ions. Thus, the liquid crystal poly(ester imide) (t‐LCPEI), carboxyl‐terminated liquid crystal poly(ester imide) (c‐LCPEI), and azabenzotriazole‐terminated liquid crystal poly(ester imide) (a‐LCPEI) were synthesized. The results showed that LCPEIs possessed liquid crystallinity, and the peel strength of a‐LCPEI film to copper foils was increased by about 140% and nearly 43%, respectively, compared to that of LCP and t‐LCPEI. Moreover, a‐LCPEI showed higher glass transition temperature (Tg = 211°C) than conventional LCP resins (Tg = 155°C, Vectra A), and excellent thermal properties. Meanwhile, the dielectric constant and loss of a‐LCPEI were as low as 3.04 and 9.7 × 10−3 at 10 GHz, respectively. These findings indicate that the azabenzotriazole‐terminated LCPEI is suitable to be used as the substrate material for high‐performance FCCL, and the work provides a feasible approach to enhance the adhesion and maintain the other outstanding properties of LCP. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) is a widely used thermoplastic engineering polymer, and the toughening modification for PA6 is always a main research topic. Meanwhile, the rigidity and heat resistance of PA6 usually deteriorate. To address this conflict, an epoxy compound (EGDE‐GA) was designed and synthesized and used to modify PA6 by dynamic vulcanization in twin‐screw extruder. EGDE‐GA is a linear molecule with a flexible molecular structure, which is favorable to toughening of PA6, and epoxy groups of EGDE‐GA can form local cross‐linked structure to improve the rigidity and retain the heat resistance of PA6. At the loading of 20 wt% of EGDE‐GA, the modified PA6 (PA6/EGDE‐GA 20) exhibited very high elongation at break and notched impact strength, which were increased by 413% and 520%, respectively, compared to those of PA6. The tensile strength was 61.4 MPa, which was higher than that of PA6. The heat deflection temperature remained almost unchanged. The results showed that the modified polymers may possess the high toughness without sacrificing the original rigidity by building the local crosslinked structure using dynamic vulcanization. The findings provide a feasible method for reusing and upcycling PA6 and other polymers with higher value and wider use in the industry. Highlights: The polyamide 6 (PA6) is toughened via dynamic vulcanization.The toughness of modified PA6 is increased by 520% compared with pure PA6.The toughened PA6 exhibits higher tensile strength than that of pure PA6.The toughened PA6 maintains its rigidity and heat resistance. [ABSTRACT FROM AUTHOR]

This study examined the relationships between children's mobile gaming preferences, online risks, and mental health. Data were obtained from a sample of 2,702 third and fourth grade students from 16 elementary schools in Taiwan and 9 schools in China. A self-administered questionnaire was used. The mental state of the children who participated in the study was assessed using the Strengths and Difficulties Questionnaire (SDQ), while mobile gaming addiction was assessed using the short form of the Internet Gaming Disorders Scale (IGDS9-SF). The results showed that about 54% of children played mobile games with others (multi-player), while 31% played mobile games alone, and 15% did not play mobile games. Multiple logistic regression results indicated that behaviors such as participating in multi-player games, playing violent games, a poor parent-child relationship, and living in a rural area were associated with a greater risk of mobile gaming addiction. Involvement in multi-player games, playing violent games, mobile gaming addiction, and exposure to mobile violence/pornography were associated with greater risks of cyber aggression/victimization. Multiple regression results showed that being a multi-player, playing violent games, mobile gaming addiction, exposure to violence/pornography, exposure to cyber aggression/victimization, and having a poor parent-child relationship were associated with emotional and behavioral problems.