Since the advancement of generative AI requires highly integrated multi-layered GPU, a large electric field is generated in copper-clad laminate (CCL) which reach high temperature. Therefore, low dielectric constants, high glass transition temperatures (Tg), and low coefficients of thermal expansion (CTE) are required for CCL resin layers. However, the pursuit of these properties is a trade-off, and the development of useful materials has been required. It has been reported that 1,2-polybutadiene (PB) which includes 1,2-vinyl units produced by living anionic polymerization has excellent low dielectric properties. In this study, we synthesized modified 1,2-PB block copolymers with enhanced thermal resistance using this method.

We found that the reaction of 4,4’-diglycidyloxydiphenyl ether with 4,4’-dihydroxydiphenyl ether produced a crystalline cured polymer. The crystalline cured polymer had excellent heat resistance corresponding to Tm, which is higher than Tg, and also showed excellent properties such as low thermal expansion, low moisture absorption and high thermal conductivity due to the improved packing of molecular chains by crystallization. By applying 4,4’-dihydroxybiphenyl as a curing agent to improve heat resistance, Tm was improved by 59.8 °C to 245.6 °C. A crystalline cured polymer was similarly obtained from 4,4’-diglycidyloxybenzophenone, and Tm increased to 230.9 °C. Furthermore, with the aim of introducing a cross-linked structure to improve heat resistance, we examined the application of 4,4’-diaminodiphenylsulfone (DDS) as a curing agent. By using 50 wt% DDS as a curing agent, it was possible to maintain crystallinity while increasing the Tg by 51.3 °C to 169.0 °C. The evaluation of the crystalline cured polymers as a molding material revealed that the thermal conductivity of molded product filled with 94 wt% alumina was 6.9 W/m･K, which was approximately twice that of molded product made from conventional bisphenol F-type epoxy resin.

In order to suppress the creep of continuous carbon fiber reinforced plastics (CFRP), the use of a Tg-less epoxy resin as a matrix was investigated. This Tg-less epoxy resin can be easily obtained by curing a standard liquid epoxy resin with an alkali metal salt of a carboxylic acid. After curing, this resin maintains a glassy state with little decrease in storage modulus even at temperatures up to 300°C. At the same time, its loss tangent is low at all test temperatures, suggesting that the-stress relaxation hardly occurs. In this study, we attempted to elucidate the curing and Tg-less mechanisms of this resin system, and also fabricated CFRP and evaluated its creep properties. Meanwhile, the brittleness of the cured Tg-less epoxy resin was overcome by modifying it with nano-rubber particles. Creep tests using a three-point bending mode showed that the creep strain rate of the Tg-less epoxy resin containing 16 wt% nano-rubber particles reached almost zero after 50 hours of testing.

Materials informatics (MI) is rapidly being adopted in industrial materials development. However, network polymers are difficult to uniquely describe their three-dimensional crosslinked structures, and the success or failure of MI application depends on the representation design of the material system. This article roughly classifies MI tasks for network polymers into (i) tasks where multiple components and conditions can be defined and (ii) tasks where a representative structure can be defined, and guidelines for selecting approaches suitable for practical applications are summarized. In the former, the importance of designing tabular datasets, focusing on formulation ratios, material types, and process conditions, is explained using the case of thermosetting resin composites. On the other hand, in the latter, three approaches, (1) descriptor-based modeling, (2) structure-based modeling using graph neural networks (GNNs), and (3) sequence-based modeling using Transformer are compared to describe their characteristics and applications. Furthermore, based on the MI approaches presented in this paper, points to consider in practical applications and future prospects of this field are described.

Tyramine triepoxide resin (TTE) was synthesized from tyramine and epichlorohydrin. Tyramine tricarbonate resin (TTC) was synthesized by reacting TTE with carbon dioxide in the presence of a lithium bromide catalyst. TTC resin was cured with stoichiometric amount of 4,7,10-trioxa-1,13-tridecanediamine (TODA) or m-xylene diamine (mXDA) by heating at 100°C for 24 hours. Thermogravimetric analysis showed that the 5% weight loss temperature was 215°C for the cured TTC/TODA resin and 208°C for the cured TTC/mXDA resin, indicating that both products were easy to be thermally decomposed. Differential scanning calorimetry and film tensile test showed that the cured TTC/TODA resin was a rubber-like flexible material at room temperature, with a glass transition temperature of －22°C, an elastic modulus of 0.76 GPa, and a maximum strength of 14.2 MPa, while the cured TTC/mXDA resin was a glass-like hard material at room temperature, with a glass transition temperature of 62°C, an elastic modulus of 6.8 GPa, and a maximum strength of 152 MPa. Shear adhesive strength to a stainless-steel substrate to a stainless substrate was-19.3 MPa for the cured TTC/TODA rein and 2.4 MPa for the cured TTC/mXDA resin. As a result of enzymatic degradation experiments using lipase and protease solutions, increases in water uptake were observed in the cured TTC/TODA resins, indicating the collapse of the molecular network structure, while almost no changes were observed in the cured TTC/mXDA resin.