02298nas a2200253 4500008004100000022001400041245012500055210006900180260000800249300000600257490000700263520141900270653002701689653001801716653002001734653002901754653001601783100002501799700002301824700002101847700002401868700002801892856012401920 2019 eng d a1022-976000aAromatic polycarbonates bearing pendant maleimide groups via functional monomer approach: synthesis and characterization0 aAromatic polycarbonates bearing pendant maleimide groups via fun cDEC a80 v273 a

A new bisphenol containing pendant maleimide group, viz., 4, 4'-(5-maleimidopentane-2, 2-diyl) diphenol (BPA-MA), was synthesized starting from commercially available 4, 4'-bis (4-hydroxyphenyl) pentanoic acid. Aromatic (co)polycarbonates possessing pendant maleimide groups were synthesized by solution polycondensation of BPA-MA or varying mixtures of BPA-MA and bisphenol-A (BPA) with triphosgene in dry dichloromethane in the presence of triethylamine as a base. Inherent viscosities and number average molecular weights of (co)polycarbonates were in the range 0.46-0.66 dL/g and 24,600-36,700, respectively, indicating the formation of reasonably high molecular weight polymers. Tough, transparent, and flexible films could be cast from chloroform solutions of these (co)polycarbonates. (Co)polycarbonates were characterized using FT-IR, H-1 NMR, C-13 NMR spectroscopy, XRD, TGA and DSC analysis. The chemical modification of a representative copolycarbonate containing pendant maleimide groups was carried out quantitatively using thiol-maleimide Michael addition reaction with two thiol compounds, namely, 4-chlorothiophenol and 1-adamantanethiol. Additionally, it was demonstrated that copolycarbonate containing pendant maleimide groups could be used to form insoluble cross-linked gel by reaction with a multifunctional thiol cross-linker, namely, pentaerythritol tetrakis(3-mercaptopropionate).

10aAromatic polycarbonate10aCross-linking10amaleimide group10aThiol-maleimide reaction10aTriphosgene1 aNagane, Samadhan, S.1 aKuhire, Sachin, S.1 aIchake, Amol, B.1 aRajamohanan, P., R.1 aWadgaonkar, Prakash, P. uhttps://library.ncl.res.in/content/aromatic-polycarbonates-bearing-pendant-maleimide-groups-functional-monomer-approach02543nas a2200253 4500008004100000022001400041245012700055210006900182260000800251300001200259490000700271520162900278653002701907653002601934653002401960653002501984653002902009100002502038700002202063700001802085700002602103700002802129856013202157 2022 eng d a1060-132500aPendant propargyloxy-functionalized aromatic (co)polycarbonates: synthesis, thermal crosslinking and chemical modification0 aPendant propargyloxyfunctionalized aromatic copolycarbonates syn cNOV a752-7630 v593 a

A bisphenol monomer bearing pendant propargyloxy group viz, 1, 1-bis (4-hydoxyphenyl)-1-(4 `-propargyloxyphenyl) ethane (BPP) was synthesized starting from commercially available 1, 1, 1-tris (4-hydroxyphenyl) ethane (THPE) by mono O-propargylation reaction using propargyl bromide. A new series of pendant propargyloxy-functionalized aromatic (co)polycarbonates was synthesized by low-temperature solution polycondensation of BPP or different molar ratios of BPP and bisphenol-A with triphosgene in dichloromethane in the presence of triethylamine. The formation of reasonably high molecular weight (co)polycarbonates was confirmed by inherent viscosity (0.52-0.83 dL/g) and gel permeation chromatography (M-n 37,000-69,800 g/mol, polystyrene standards) measurements. C-13 NMR spectral studies supported formation of random copolycarbonates in copolymerization of BPP and BPA with triphosgene. The 10% weight loss temperature (T-10) values of (co)polycarbonates, determined by thermogravimetric analysis under nitrogen atmosphere, were in the range 427-438 degrees C indicating their good thermal stability. The glass transition temperature (T-g) values of (co)polycarbonates were observed in the range 147-152 degrees C. The crosslinking ability of (co)polycarbonates involving pendant propargyloxy groups leading to formation of networked structure was evaluated via non-isothermal curing studies by DSC. As a proof-of-concept, the post-modification of a representative polycarbonate bearing pendant propargyloxy groups with 1-octane thiol as a model compound via thiol-yne click reaction was briefly studied.

10aAromatic polycarbonate10aChemical modification10apropargyloxy groups10athermal crosslinking10athiol-yne click reaction1 aNagane, Samadhan, S.1 aMaher, Deepak, M.1 aVerma, Savita1 aTalanikar, Aniket, A.1 aWadgaonkar, Prakash, P. uhttps://library.ncl.res.in/content/pendant-propargyloxy-functionalized-aromatic-copolycarbonates-synthesis-thermal-crosslinking02425nas a2200265 4500008004100000022001400041245011200055210006900167260000800236300001500244490000600259520150600265653002701771653002401798653003001822653001601852653002001868100002501888700002301913700002101936700002601957700002001983700002802003856012802031 2022 eng d a2365-654900aSynthesis, characterization and UV-crosslinking of aromatic (Co)polycarbonates bearing pendant azido groups0 aSynthesis characterization and UVcrosslinking of aromatic Copoly cSEP ae2022010200 v73 a

A new series of (co)polycarbonates bearing pendent azido groups was synthesized by polycondensation of varying molar proportions of 4, 4'-(5-azidopentane-2, 2-diyl) diphenol and bisphenol-A with triphosgene. The chemical structures, compositions and random nature of (co)polycarbonates were confirmed by NMR spectroscopy. Inherent viscosities and number-average molecular weights of (co)polycarbonates were in the range 0.63-0.77 dL g(-1) and 35,400-43,400 g mol(-1), respectively indicating the formation of reasonably high molecular weight polymers. (Co)polycarbonates could be cast into tough, transparent and flexible films from chloroform solutions. (Co)polycarbonates were further characterized using IR spectroscopy, XRD, TGA and DSC. The thermal crosslinking of (co)polycarbonates bearing pendant azido groups was studied by DSC analysis. Independently, (co)polycarbonates bearing pendant azido groups were exposed to UV irradiation at wavelength of 254 nm and decomposition reaction of azido groups was monitored by FT-IR spectroscopy. The complete decomposition of azido groups was observed with exposure time of 30 min. The formed cross-linked (co)polycarbonates exhibited improved % char yield values compared to parent (co)polycarbonates. The measurement of mechanical properties of representative crosslinked (co)polycarbonates indicated increase in tensile strength and Young's modulus and decrease in % elongation compared to corresponding parent linear (co)polycarbonates.

10aAromatic polycarbonate10aPendant azido group10asolution polycondensation10aTriphosgene10aUV-crosslinking1 aNagane, Samadhan, S.1 aKuhire, Sachin, S.1 aIchake, Amol, B.1 aTalanikar, Aniket, A.1 aLochab, Bimlesh1 aWadgaonkar, Prakash, P. uhttps://library.ncl.res.in/content/synthesis-characterization-and-uv-crosslinking-aromatic-copolycarbonates-bearing-pendant