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Developing effective latent curing agent for rapid curing of epoxy resins at low temperatures remains challenging. This study reports a latent curing agent, ortho‐cresol phenolic epoxy resin‐bisphenol A (EOCN‐BPA), prepared through the addition reaction of o‐methyl phenolic epoxy resin with BPA. When blended with dicyandiamide (DICY) in a 1:3 molar ratio, EOCN‐BPA/DICY is used to cure a linear epoxy phenolic novolac (EPN) resin (epoxy equivalent: 550 g eq−1, softening point: approximately 82°C), at an onset curing temperature of 90°C, which is considerably lower than the onset curing temperature of DICY with EPN (160°C). However, EOCN‐BPA does not react with EPN without a catalyst. Therefore, this latent curing system is successfully applied in powder coatings, rapid curing at 120°C within 3 min without an additional catalyst, outperforming the EPN/EOCN‐BPA system using cocatalyst 2‐methylimidazole. Consequently, DICY catalyzes the curing reaction between the phenol hydroxyl group and epoxy resin and participates in it. The prepared powder coating exhibits excellent storage stability, maintaining its properties for over 3 months at room temperature. These findings demonstrate the excellent latent properties of EOCN‐BPA/DICY, highlighting its potential as a highly effective latent curing agent. [ABSTRACT FROM AUTHOR]

In view of demand of lighter thermal protection system for our national space vehicle，recent development of investigation and practical application of lightweight thermal protection ablation materials are summarized systematically at home and abroad，in which the silicon or resin reinforced with honeycomb structural reinforcement and resin impregnated fibrous substrate ablators are included，focuses On silicone resin reinforced with glass，silica or carbon fiber/phenolic honeycomb as well as silicon，phenolic and Silicone Impregnated Reusable tendency Ceramic Ablator(SIRCA) and Phenolic Impregnated Carbon Ablator( in the future of aboard lightweight ablators is proposed，which can PICA)，finally the development directly borrow or simply draw inspiration for our country in this field.

As a rising star in the area of soft luminescent materials, clusteroluminescence (CL) polymers without large π-conjugated structures have received considerable attention in recent years owing to their great theoretical significance and potential applications. Herein, poly(vinylene carbonate) (PVC) and poly(vinylethylene carbonate) (PVEC) containing only oxygen heteroatoms are prepared and exhibit blue photoluminescence (PL) with excitation/molecular weight-dependent and concentration-enhanced emission properties. The PL quantum yields of PVC and PVEC in dimethyl sulfoxide can reach 11.5% and 13.1%, respectively. The experimental results show that CL will appear above the critical degree of polymerization (DP); within a certain range of DP, the quantum yield increases rapidly with increasing DP, and eventually tends to be constant, confirming the theory of polymerization-induced emission (PIE). Theoretical calculations reveal that the high molecular weight can greatly promote the formation of oxygen clusters and the through-space n–n interaction (TSI-n–n) of oxygen atoms, while the rigid molecular conformation further stabilizes them, enabling fluorescence emission. Moreover, benefiting from the ultra-high molecular weight (1436.7 KDa) of PVC, electrospun fibers, electrosprayed microspheres, and sponges were prepared, providing a new platform for the rational molecular design of functional CL materials. [ABSTRACT FROM AUTHOR]

Double hydrosilylation of alkynes represents a straightforward method to synthesize bis(silane)s, yet it is challenging if α‐substituted vinylsilanes act as the intermediates. Here, a cobalt‐catalyzed regiodivergent double hydrosilylation of arylacetylenes is reported for the first time involving this challenge, accessing both vicinal and geminal bis(silane)s with exclusive regioselectivity. Various novel bis(silane)s containing Si−H bonds can be easily obtained. The gram‐scale reactions could be performed smoothly. Preliminarily mechanistic studies demonstrated that the reactions were initiated by cobalt‐catalyzed α‐hydrosilylation of alkynes, followed by cobalt‐catalyzed β‐hydrosilylation of the α‐vinylsilanes to deliver vicinal bis(silane)s, or hydride‐catalyzed α‐hydrosilylation to give geminal ones. Notably, these bis(silane)s can be used for the synthesis of high‐refractive‐index polymers (nd up to 1.83), demonstrating great potential utility in optical materials. [ABSTRACT FROM AUTHOR]

A bismaleimide monomer, 4,4'-bis(4-maleimidophenoxy)-3,3',5,5'-tetramethyl biphenol (BMITB), was synthesized in high yield (94%) via a facile four-step reaction from 2,2',6,6'-tetramethyl-4,4'-biphenol. The chemical structure of BMITB was confirmed by FTIR, [sup.1.H] NMR, [.sup.13]C NMR and elemental analysis. The monomer used to modify the epoxy cresol-formaldehyde novolac resin (ECN)/diaminodiphenyl sulfone (DDS) system. Cured ECN/BMITB/DDS blends with higher BMITB content had two distinct glass transition temperatures that were above 250°C according to differential scanning calorimetry, indicating that an interpenetrated polymer network structure may be formed. The initial thermal decomposition temperature and integral procedure decomposition temperature of the cured ECN/BMITB/DDS blends were >390 and 1080°C, respectively, according to thermogravimetric analyses. No phase separation was observed in dynamic mechanical analysis of cured ECN/BMIT/DDS blends with small amounts of BMITB (5 and 10 wt%). POLYM. ENG. SCI., 49:1525-1532, 2009. © 2009 Society of Plastics Engineers, INTRODUCTION Epoxy resins possess good adhesive, physical, dielectric, and mechanical properties and excellent processability, which are required for an ideal matrix resin in structural composites for aerospace applications. However, their [...]