@article {48386, title = {Reinforcement of electrospun polyurethane fibers with resorcinol-formaldehyde resin}, journal = {Journal of Applied Polymer Science}, volume = {139}, year = {2022}, month = {MAY}, pages = {e52007}, type = {Article}, abstract = {

This work reports a simple method to improve the properties of electrospun nanofibers. The procedure involves developing nanofibers using electrospinning followed by liquid infiltration to reinforce the fibers. Coating of polyurethane nanofibers (PUN) with resorcinol-formaldehyde (RF) significantly improves the properties of PUN. Furthermore, the morphology of fiber interface and the properties of RF coated fibers indicate that RF resin reinforces the interface between the fibers. The method leads to improvement in mechanical properties of PUN. An improvement of about 94\% and 281\% in mechanical properties like tensile strength and modulus, respectively, compared to neat PUN fibers is achieved by coating with 20\% wt/vol of RF solution.

}, keywords = {Dynamic mechanical analysis, electrospinning, liquid infiltration, polyurethane, reinforced nanofibers, resorcinol-formaldehyde}, issn = {0021-8995}, doi = {10.1002/app.52007}, author = {Nair, Kiran Sukumaran and James, Nirmala Rachel} } @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} } @article {49293, title = {Biobased reusable nonisocyanate polyurethane hot-melt adhesives with potential chemical degradability}, journal = {ACS Applied Polymer Materials}, volume = {6}, year = {2024}, month = {SEP}, pages = {11180-11192}, type = {Article}, abstract = {

Hot-melt adhesives (HMAs) derived from renewable resources are always attractive, as they promote less dependence on fossil resources and aid in developing environmentally friendly materials. However, developing sustainable HMAs exhibiting good adhesive performance and biodegradability remains challenging. Herein, reusable biobased HMAs with a high bio content of 88-90\%, biodegradability, and tunable adhesive nature were developed as a possible alternative to conventional petroleum-based hot-melt adhesives. Moreover, the structure-property relationship of the product was investigated in detail. By tailoring the monomer composition, NIPU-40 HMA exhibited a good bonding ability with a superior adhesion strength of 6.39 MPa. To the best of our knowledge, this is the highest adhesion strength observed when bonding with an Al substrate among the biobased thermoplastic NIPU-HMAs. Impressively, NIPU-HMAs could display excellent reusability even after three bonding and debonding cycles without a significant drop in the adhesive strength and were found to exhibit good adhesion performance under wet conditions. More importantly, the NIPU-HMAs are prone to degradation under acid-catalyzed conditions. Considering their features, these biobased NIPU thermoplastic hot-melt adhesives offer an opportunity to create environmentally friendly, degradable adhesives that possess excellent adhesive strength and can be reused multiple times.

}, keywords = {acid degradability, biobased NIPUs, cyclic carbonates, hot meltadhesives, lap shearstrength, spiro-aromatic}, issn = {2637-6105}, doi = {10.1021/acsapm.4c01526}, author = {Ghuge, Gorakh Hiraman and Torris, Arun and Nair, Kiran Sukumaran} } @article {49087, title = {Biodegradable and 3D printable lysine functionalized polycaprolactone scaffolds for tissue engineering applications}, journal = {Biomaterials Advances}, volume = {159}, year = {2024}, month = {MAY}, pages = {213816}, type = {Article}, abstract = {

Tissue engineering (TE) has sparked interest in creating scaffolds with customizable properties and functional bioactive sites. However, due to limitations in medical practices and manufacturing technologies, it is challenging to replicate complex porous frameworks with appropriate architectures and bioactivity in vitro. To address these challenges, herein, we present a green approach that involves the amino acid (L-lysine) initiated polymerization of epsilon-caprolactone (CL) to produce modified polycaprolactone (PCL) with favorable active sites for TE applications. Further, to better understand the effect of morphology and porosity on cell attachment and proliferation, scaffolds of different geometries with uniform and interconnected pores are designed and fabricated, and their properties are evaluated in comparison with commercial PCL. The scaffold morphology and complex internal micro-architecture are imaged by micro-computed tomography (micro-CT), revealing pore size in the range of similar to 300-900 mu m and porosity ranging from 30 to 70 \%, while based on the geometry of scaffolds the compressive strength varied from 143 +/- 19 to 214 +/- 10 MPa. Additionally, the degradation profiles of fabricated scaffolds are found to be influenced by both the chemical nature and product design, where Lys-PCL-based scaffolds with better porosity and lower crystallinity degraded faster than commercial PCL scaffolds. According to in vitro studies, Lys-PCL scaffolds have produced an environment that is better for cell adhesion and proliferation. Moreover, the scaffold design affects the way cells interact; Lys-PCL with zigzag geometry has demonstrated superior in vitro vitality (\>90 \%) and proliferation in comparison to other designs. This study emphasizes the importance of enhancing bioactivity while meeting morphology and porosity requirements in the design of scaffolds for tissue engineering applications.

}, keywords = {Additive manufacturing, Amino acid, Micro-computed tomography, Polycaprolactone}, doi = {10.1016/j.bioadv.2024.213816}, author = {Naik, Sonali S. and Torris, Arun and Choudhury, Namita R. and Dutta, Naba K. and Nair, Kiran Sukumaran} } @article {49549, title = {Optimization and mechanistic insights of zinc ascorbate catalyst for ring-opening polymerization of caprolactone using RSM methodology and DFT calculations}, journal = {Polymers for Advanced Technologies}, volume = {36}, year = {2025}, month = {APR}, pages = {e70182}, type = {Article}, abstract = {

Polycaprolactone (PCL) is an aliphatic polyester recognized for its exceptional versatility and biodegradability, which has garnered significant attention for a wide range of applications. This study presents an innovative methodology for the synthesis of PCL through the ring-opening polymerization (ROP) of epsilon-caprolactone (CL). The approach employs a biocompatible and environmentally benign organometallic zinc ascorbate complex as a catalyst. Derived from ascorbic acid, a well-established reducing agent, zinc ascorbate serves as a sustainable alternative to conventional tin-based catalysts, thereby mitigating environmental impact and enhancing safety measures. The catalyst operates effectively under solvent-free conditions and does not require initiators, achieving a high polymer conversion rate of approximately 79\%. The optimization of the reaction parameters was conducted using response surface methodology (RSM) employing a central composite design (CCD). The structural and chemical characterization of the catalyst as well as the resulting polymers was performed using proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) analyses. Additionally, density functional theory (DFT) calculations elucidated a four-step coordination-insertion mechanism for the polymerization of cyclic lactones, with findings supported by Gibbs free energy, electrostatic potential, and non-covalent interactions. This study underscores the potential of zinc ascorbate as a reliable, nontoxic, and cost-effective catalyst, fulfilling the increasing demand for sustainable and efficient polymerization processes in commercial and biomedical applications.

}, keywords = {density function theory, Polycaprolactone, Response surface methodology, ring-opening polymerization, zinc ascorbate}, issn = {1042-7147}, doi = {10.1002/pat.70182}, author = {Naik, Sonali S. and Vedpathak, Shantanu and Nair, Kiran Sukumaran} } @article {49268, title = {Thrombin immobilized hemocompatible radiopaque polyurethane microspheres for topical blood coagulation}, journal = {JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A}, volume = {113}, year = {2025}, month = {JAN}, type = {Journal Article}, keywords = {ALGINATE MICROSPHERES, ENDOVASCULAR TREATMENT, PRECISE LOCALIZATION}, issn = {1549-3296}, doi = {10.1002/jbm.a.37828}, author = {Naik, Sonali S. and Torris, Arun and Ghuge, Gorakh Hiraman and Karthika, V. K. and Joseph, Roy and Nair, Kiran Sukumaran} } @article {49519, title = {Triple G-C-T base-coded self-assembling water-soluble nucleobase monomers with a broad scope for biomaterial and protein bioconjugation applications}, journal = {Journal of Organic Chemistry}, volume = {90}, year = {2025}, month = {FEB}, pages = {2822-2829}, type = {Article}, abstract = {

We report self-assembling water-soluble nucleobase monomers with a broad scope for biomaterial and protein bioconjugation applications. These nucleobase monomers are adorned with nature-inspired triple G-C-T nucleobases featuring three recognition sites: DDA (G mimic), DAA (C mimic), and ADA (T mimic). Using readily accessible starting materials, these monomers can be synthesized in excellent yields, making them good choices for diverse applications. Their unique structural features, coupled with their water solubility, may offer exciting opportunities for the creation of new biomaterials.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.4c02745}, author = {Singh, Dharmendra and Gone, Nilu V. and Bandi, Kiran and Davis, Disiya and Nair, Kiran Sukumaran and Sanjayan, Gangadhar J.} }