Pan Tian,Shengdu Yang,Ningning Hou,Keyu Lian,Wanjing Liu,Junhua Zhang
With the booming of the electronics industry, solder resist (SR) inks used in printed circuit boards (PCBs) face increasingly stringent performance requirements, including storage modulus, heat resistance, dielectric properties, and alkaline developability, posing more challenges for the rational design of molecular structures. Herein, through the reaction of biphenyldicarboxylic acid (BPDA) with naphthalene-type epoxy (NDE), a series of epoxy resins bearing biphenyl structures in the main chain were synthesized, while 4-aminobiphenyl (ABP) was introduced to obtain epoxy resins with biphenyl structures in the side chain. Subsequently, main-chain (NM x AT) and side-chain (NS x AT) photocurable resins were prepared through sequential reactions with acrylic acid and tetrahydrophthalic anhydride. The effect of the introduction amount of biphenyl on the properties of the resin and its cured film was systematically investigated. Meanwhile, detailed comparisons were conducted to examine the property differences between biphenyl structures in the main chain and side chains, respectively. The contention that large spatial structures can effectively increase molecular free volume ratio was verified by using molecular dynamics simulations and a molecular model of a double-bonded cross-linked network. As a conclusion, chain extension needs to be controlled at a low molecular weight (≈1100 g mol -1 ) to inhibit the chain movement, thereby effectively improving the modulus of the resin. Additionally, large spatial structures mitigate the decrease of heat resistance caused by chain extension and effectively lower the dielectric constant. Ultimately, the preferred photocurable resins (NM 10 AT) were developed as SR inks for PCB applications, providing a strategy to enhance the performance of photocurable resins and constructing molecular models of double-bonded crosslinked networks.
With the advancement of minimally invasive interventional therapy, biological heart valves (BHVs) have been extensively used in clinics. However, BHVs are generally prone to degeneration within 10–15 years after implantation due to defects including cytotoxicity, immune response, calcification and thrombosis, which are closely related to glutaraldehyde-crosslinking. In this work, we prepared a functionalized BHV through the in situ polymerization of methacrylated porcine pericardium and 2-hydroxyethyl methacrylate to avoid and overcome the defects of glutaraldehyde-crosslinked BHVs. The functionalized BHV was proven to be stable against enzymatic degradation and compatible towards HUVECs. After implantation in rats subcutaneously, a significantly mitigated immune response and reduced calcification were observed in the functionalized BHV. With the grafting of hydrophilic 2-hydroxyethyl methacrylate polymers, the antithrombogenicity of BHV was markedly enhanced by resisting the unfavorable adhesion of blood components. Moreover, the hydrodynamics of the functionalized BHV totally conformed to ISO 5840-3 under a wide range of simulated physiological conditions. These results indicate that the functionalized BHV with enhanced biocompatibility, anticalcification property and antithrombogenicity exhibited a low risk of degeneration and should be explored for further application.
危险品化学品经营许可证（带存储）