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Crystalline porous molecular frameworks formed through intermolecular hydrogen bonding calling hydrogen-bonded organic frameworks (HOFs) have recently been investigated as a new family of functional porous materials. In this review, HOFs composed of tritopic, tetratopic, and hexatopic carboxylic acid derivatives, which form H-bonded network such as those with hcb, sql, and hxl topologies depending on the numbers, positions, and orientations of the carboxy groups and conformational flexibility of the molecular skeletons, are reviewed by considering structural aspects such as isostructurality.
Thermal curing of maleimidobenzoxazines (MB-Rs) with n-butyl, 2-ethylhexyl, allyl, and phenyl substituents was carried out in the presence of tetrafunctional thiols with pentaerythritol and glycolurea cores. The thermosets were prepared by the following curing processes: directly curing the mixtures at 140–160 °C and postcuring the building block. The effects of the network polymer structures on the thermal stability and mechanical properties of the thermosets were investigated. The thermosets showed excellent decomposition temperatures, i.e., Td5 = 215–309 °C and Td50 = 318–587 °C. The mechanical properties were modified by introducing a 2-ethylhexyl group, and stretchable and bendable thermosets were obtained.
Series of propylene (C3) and hexylene (C6)-linked tripod-shaped polyhedral octasilsesquioxane (POSS) derivatives were prepared corner-opening type POSS (COPOSS) with completely condensed POSSs (CC-POSSs). The annealed cast films of the tripodal POSSs were optically transparent, except those consisted of the phenylsubstituted CC-POSS, which were rather turbid. The tripodal POSSs showed endothermic peaks corresponding to melting (Tm) and suggest that including the phenyl-substituted CO-POSS unit reduced Tms compared with the isobutyl-substituted CO-POSS.
Lentinan (Len) is a linear (1,3)-β-d-glucan with two of its five main-chain glucose-bearing (1,6)-β-d-glucan side chains and has been clinically used for cancer treatment in combination with chemotherapy. In this paper, a structural analysis of Len was conducted using SAXS, GPC, and 13C quantitative NMR techniques, and a comparative study with other β-glucans was performed. The complexation between dA40 and Len caused the hypochromic effect. Len and dA40 showed a similar complexation with that of SPG; two main chain glucoses bind to one dA moiety by GPC.
The effects of the addition of a hyperbranched polymer (HBP) on the degradability characteristics of linear polyglycolide (PGA) fiber mats. It was revealed that HBP acted as a plasticizer, especially in underwater environments. The weight loss of the PGA fiber mats was accelerated with increasing HBP content. Considering that the structural changes in the PGA crystals depended on the feed amount of HBP, it was claimed that HBP promoted PGA degradation in both the amorphous and crystalline phases.
