Enhanced thermostability of polylactic acid by N-(4-carboxyphenyl) maleimide–alt–styrene

The heat-resistant agent N-(4-carboxyphenyl) maleimide–alt–styrene (PCS) was used to modify polylactic acid (PLA) in order to improve the thermostability of PLA. The heat deflection temperature (HDT), thermodegradation, crystallization behavior and thermomechanical property were analyzed. The HDT of PLA added with PCS increased by about 10°C, and after heat treatment, the improvement of HDT was more significant. The thermal degradation behavior of PLA before and after modification hardly changed. The crystallinity ( Xc), crystallization rate ( 1/t1/2) and crystallization temperature ( Tc) of the composite material were significantly improved, but the crystalline structure did not change. The crystallinity of the composite material was twice that of pure PLA, the crystallization rate increased by about 30% and the crystallization temperature went up more than 10°C. The storage modulus ( E’) of PLA was improved by PCS due to enhancing its crystallinity. The thermostability of PLA was significant improved after PCS is added.

Correction: Enhanced thermomechanical property of a self-healing polymer via self-assembly of a reversibly cross-linkable block copolymer

Correction for ‘Enhanced thermomechanical property of a self-healing polymer via self-assembly of a reversibly cross-linkable block copolymer’ by Hyang Moo Lee et al., Polym. Chem., 2020, DOI: 10.1039/d0py00310g.

Enhanced thermomechanical property of a self-healing polymer via self-assembly of a reversibly cross-linkable block copolymer

Introduction of a self-healable block copolymer increases the mechanical property whilst maintaining self-healing efficiency.

Curing behavior, thermal, and mechanical properties of N,N′-(4,4′-diphenylmethane)bismaleimide/2,2′-diallylbisphenol A/3-allyl-5,5-dimethylhydantoin resin system

The 3-allyl-5,5-dimethylhydantoin (ADMH) was synthesized and characterized by Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance (NMR), and 13C-NMR spectroscopy. Then, the ADMH was used to modify the N, N′-(4,4′-diphenylmethane)bismaleimide (BDM)/2,2′-diallylbisphenol A (DABPA) resin to obtain the BDM/DABPA/ADMH resin system (BDA). The curing behavior was investigated by non-isothermal differential scanning calorimetry and the activation energy ([Formula: see text]) was obtained by Kissinger and Ozawa models. The thermomechanical property was measured by dynamic mechanical analysis. Analysis of the data revealed the complexity of the curing reaction, which was firstly dominated by the Ene reaction of allyl and C=C double bond at low and medium temperatures and was further governed by the Diels–Alder reaction and the anionic imide oligomerization occurred at high temperatures. The results demonstrated that 1-BDA had the best thermal and mechanical properties exhibiting excellent modification effect of ADMH.

Carbon-fibre-reinforced modified cyanate ester winding composites and their thermomechanical properties

Although the extensive research has expanded on the modification of cyanate ester (CE) resins and the mechanical properties of CE composites, very few studies have been conducted on carbon fibre (CF)/modified CE winding composites and the thermomechanical properties of the composites. In this research, epoxy (EP)-modified novolac cyanate ester (NCE) and bismaleimide (BMI)-modified NCE resins were prepared. The CF/modified CE winding composites were manufactured, and their thermomechanical properties were tested. The optimal winding process was determined, and a preheating technique was implemented. Then, the EP/CE resin (10:90) and the BMI–DBA/CE resin (10:90) were selected as the resin matrix of the winding composite based on the viscosity properties, mechanical properties and thermal analysis (using thermogravimetric analysis and differential scanning calorimetry) of the modified CE resin. The selected resin exhibited good manufacturability at 70°C, good thermal stability and high Tg (above 370°C). The thermomechanical property tests indicate that the modified CE resin composite exhibits an outstanding mechanical strength at room temperature and at high temperatures (130°C, 150°C and 180°C) compared with that of the pure CE resin composite. The reasons for this enhancement can be attributed to a toughening mechanism and the effect of sizing agents on the CFs.