@article {43796, title = {Partially bio-based poly(amide imide)s by polycondensation of aromatic diacylhydrazides based on lignin-derived phenolic acids and aromatic dianhydrides: synthesis, characterization, and computational studies}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {55}, year = {2017}, month = {NOV}, pages = {3636-3645}, type = {Article}, abstract = {

Two new bio-based diacylhydrazide monomers, namely, 4,4-(propane-1,3-diylbis(oxy))bis(3-methoxybenzohydrazide) and 4,4-(propane-1,3-diylbis(oxy))bis(3,5-dimethoxybenzohydrazide) were synthesized starting from lignin-derived phenolic acids, namely, vanillic acid and syringic acid. A series of poly(amide imide)s was synthesized by polycondensation of these diacylhydrazide monomers with commercially available aromatic dianhydrides. Poly(amide imide)s showed inherent viscosity in the range 0.44-0.56 dLg(-1) and exhibited good solubility in organic solvents. Poly(amide imide)s could be cast into transparent, flexible, and tough films from their N,N-dimethylacetamide solutions. Poly(amide imide)s showed 10\% weight loss in the temperature range 340-364 degrees C indicating their good thermal stability. Glass transition temperature (T-g) of poly(amide imides)s were measured by DSC and DMA which were in the range 201-223 degrees C and 214-248 degrees C, respectively. The T-g values of poly(amide imide)s were dependent on the number methoxy substituents on aromatic rings of diacylhydrazide monomers. Molecular dynamics simulation studies revealed that chain rigidity is the dominant factor for observed trends in T-g. (c) 2017 Wiley Periodicals, Inc.

}, keywords = {Biobased Polymers, Computational studies, Glass-transaction temperature, lignin, Monomers, Plant oils, Polyimide, Reneable resources, Renewable resources, Step-growth polymers, structure-property relations, Sustanaible Polymers, Thermal night, Thermosetting resins, Vanillin}, issn = {0887-624X}, doi = {10.1002/pola.28748}, author = {Kuhire, Sachin S. and Sharma, Pragati and Chakrabarty, Suman and Wadgaonkar, Prakash P.} } @article {44199, title = {First total synthesis of (+/-)-rhodoconferimide}, journal = {Synthesis-Stuttgart}, volume = {50}, year = {2018}, month = {FEB}, pages = {658-662}, type = {Article}, abstract = {

Starting from vanillin and dimethyl maleate, a concise and efficient racemic total synthesis of the potent antioxidant marine natural product (+/-)-rhodoconferimide has been carried out via the Wittig reaction, catalytic hydrogenation, selective brominations, and imide formation. An appropriate regioselective double bromination of the aromatic ring was a key step in the synthesis.

}, keywords = {(+/-)-rhodoconferimide, Antioxidants, Bromination, Natural products, Total synthesis, Vanillin}, issn = {0039-7881}, doi = {10.1055/s-0036-1590944}, author = {Pandhade, Kailas R. and N. P. Argade} } @article {48682, title = {Evaluation of the adhesive properties of vanillin-derived polyhydroxy urethanes}, journal = {Journal of Applied Polymer Science}, volume = {140}, year = {2023}, month = {Dec}, pages = {e54647}, type = {Article}, abstract = {

Poly(hydroxy urethanes) (PHUs) have been considered attractive and safer variants of conventional polyurethanes (PUs). To improve the prerequisites of green and sustainable chemistry herein, we propose the synthesis and utilization of cyclic carbonate monomers majorly derived from vanillin, a lignin derivative, and CO2 for the development of PHUs. Kinetic evaluation on the polymerization temperature ascertained 80 degrees C as the optimum condition for PHU synthesis. The structural evaluation of PHUs was carried out by various spectroscopic techniques, such as FTIR, (HNMR)-H-1, and C-13-NMR, molar masses were determined by gel permeation chromatography (Mn varied between 2500 and 11,100 g/mol), and thermal properties evaluated by differential scanning calorimeter (Tg in the ranges of 28-42 degrees C), and thermogravimetric analysis (stable above 180 degrees C). Since the PHUs are enriched with pendant hydroxyl groups on their backbone which can promote adhesion, lap shear studies on the aluminum substrate exhibited a maximum shear strength of 1.65 +/- 0.37 MPa. This study demonstrates an attractive and environment-friendly pathway for developing novel PHUs network using renewable biobased resources and further explores its applicability as adhesives.

}, keywords = {adhesive, biobased cyclic dicarbonate, diamines, poly(hydroxyurethane)s, Vanillin}, issn = {0021-8995}, doi = {10.1002/app.54647}, author = {Ghuge, Gorakh Hiraman and Kambikanam, Karthika Vayalachery and Nair, Kiran Sukumaran} }