Synthesis of Bi- and Trifunctional Cyclic Carbonates Based on Trimethylolpropane and Their Application to Networked Polyhydroxyurethanes

Abstract

The reaction of trimethylolpropane (TMP) and diphenyl carbonate gives three types of TMP-based six-membered cyclic carbonates (TMPCs) via phosgene-free route. TMPC having one hydroxyl group (TMPC-OH) reacted with terephthaloyl chloride or trimesoyl chloride to give bifunctional (Ph-TMPC 2 ) or trifunctional cyclic carbonate monomers (Ph-TMPC 3 ), respectively. The ring-opening polyaddition of Ph-TMPC 2 and conventional diamines efficiently proceeded without the cleavage of ester bonds to afford linear polyhydroxyurethanes (PHUs) with well-controlled molecular weights and polydispersities via isocyanate-free route. Moreover, the polyaddition of Ph-TMPC 2 and diamine at TMPC 2 /diamine feed ratio of 1.1 afforded PHUs having cyclic carbonate terminals, the hydroxyl side chains of which were easily reacted with acetic anhydride to give acetylated PHUs with cyclic carbonate terminals. On the other hand, the polyaddition at Ph-TMPC 2 /diamine feed ratio of 0.91 gave PHUs with amine terminals. The copolymerization of Ph-TMPC 2 , Ph-TMPC 3 and diamine gives PHUs comprising covalently-bridged networked structures. After DMF solutions of Ph-TMPC 2 , Ph-TMPC 3 and diamines were simply kept at 60 °C overnight, networked PHU films with well transparency were successfully fabricated. The PHU films prepared at different diamines showed similar transparency and thermal stability, while the mechanical properties were significantly affected by the methylene spacers of diamines.

Production and Characterization of Non-Isocyanate Polyurethane/SiO2 Films Through a Sol-Gel Process for Thermal Insulation Applications

“…Polymeric materials were obtained from the manufactured PHUs and different concentrations (20, 30 and 40%) of silica nanoparticles, named P2 (20%), P3 (30%) and P4 (40%), respectively. As can be seen in the polymers’ IR spectra (Figure 16), significant absorption bands at 3350 cm −1 , 1640 cm −1 , and 1570 cm −1 are representative of the urethane group [14,30] as well as the band at 1050 cm −1 corresponding to the Si–O–Si bonds of silica nanoparticles [22,23,24], which confirmed the successful introduction of SiO 2 NPs in the polymeric matrix. The variation in transmittance intensity of the three polymers, but more in P3 (30%) and P4 (40%), is attributed to the presence of more functional groups in their structure, while the displacements between 1400 and 1600 cm -1 are due to different arrangement of the bonds of the principal chain influenced by the addition of more silica nanoparticles.…”

“…The cyclic carbonates are opened by secondary amines and the signals arising from carbonates changed from 1700 cm −1 to 1637 cm −1 due to a urethane bond [29] forming hydroxyurethanes with cyclic carbonates (Figure 12a). The peak at 1637 cm −1 is assigned to the stretching vibrations of the carbonyl groups of urethane bonds, indicating the presence of a hydroxyurethane linkage, as identified by [30] Another band at 3330 cm −1 can be attributed to the hydroxyl groups [11] of the polymeric matrix that occurs by the ring-opening polymerization -offered by PVA-, and to N–H stretching [31,32] very close to the reference value (see Table 5). Intensity changes as a function of time are noted, which prove the polymerization process has occurred.…”

Functionalization of hydroxyl groups in segmented polyhydroxyurethane eliminates nanophase separation

“…PHU is analogous to PU but possesses an additional hydroxyl group adjacent to every urethane linkage . Although there have been numerous studies on PHU synthesis in recent years, relatively few studies have been focused on segmented, nanophase‐separated PHUs . A significant fraction of conventional PU is segmented copolymer …”

Phosgene‐Free Syntheses and Hydrolytic Properties of Water‐Soluble Polyhydroxyurethanes with Ester–Carbonate–Ether Structures in Their Main Chains

“…The development of synthetic routes to cyclic carbonates without toxic phosgene‐associated agents is important for the chemistry of polycarbonates and PHUs. We have recently reported the facile synthetic routes to mono and bifunctional 6‐CCs using diphenyl carbonate (DPC) . Without phosgene and its derivatives, DPC can be synthesized from ethylene carbonates through the reaction with methanol and phenol or directly obtained from CO and phenol .…”

“…Thus, the synthesis of 6‐CCs using DPC is one of phosgene and its derivative‐free route. In particular, by reacting trimethylolpropane (TMP) or di(trimethylolpropane) (DTMP) and an excess amount of DPC, we successfully synthesized different structured TMP‐based carbonates (TMPCs) shown in Scheme . Among them, it is expected that bifunctional 6‐CCs can be reacted with diamines to form easily PHUs having ester, carbonate or ether structures in their repeating units.…”