Influence of chitosan/1,4-butanediol blends on the thermal and surface behavior of polycaprolactone diol-based polyurethanes

Transformative enhancement of cellulosic textile properties via metallic oxide deposition: Comprehensive analysis of structural, optical, and thermoelectric traits

This novel research addresses the critical need for sustainable and efficient materials, aiming to enhance the optical and thermoelectric properties of Aluminum doped Zinc Oxide (Al-doped ZnO) on cellulose fabric for diverse applications. At first stage, Cellulosic fabric of Al-doped ZnO were experimentally studied in detail with respect to varying levels of annealing temperature. Structural analysis unveiled structural evolution in hexagonal crystal formations with a reduction in particle size up to 27.5 % on average, with increased temperature. Further, Raman spectroscopy revealed the doping effects on the vibrational modes of ZnO, potentially due to alterations in lattice structure. The ZnO optical modes are found as E2 (low) = 110 cm-1 with observed phonon frequency in the Raman spectra of ZnO at A1 (TO) = 364 cm-1. Fourier transform infrared spectroscopy (FTIR) revealed the presence of characteristic stretching of developed material. Furthermore, the optical characters revealed a decrement of 43.22 % in bandgap values with increasing annealing temperature. The analysis of thermoelectric attributes documented that the prominent sample annealed at 300°C exhibited the maximum Seebeck coefficient and power factor of 2.1 × 10-3 μV/oC and 5.8 × 10-21 Wm-1 K-2, respectively. At second stage the optical characteristics of experimentally optimized sample were rigorously studied through the application of Material Studio software, while varying the doping ratio.

Effect of branched 1,4-butanediol citrate oligomers with different molecular weights on toughness and aging resistance of glycerol plasticized starch

The thermoplastic starch with glycerol is easy to retrograde and sensitive to hygroscopicity. In this study, branched 1,4-butanediol citrate oligomers with different molecular weights (P1, P2, and P3) are synthesized, and then mixed with glycerol (G) as the co-plasticizers to prepare thermoplastic starch (CS/PG). The results show that the molecular weight and branching degree of the branched 1,4-butanediol citrate oligomers increase as reaction time prolongs. Compared with glycerol plasticized starch, the thermoplastic starch films with branched 1,4-butanediol citrate oligomers/glycerol (10 wt%/20 wt%) have a better toughness, transmittance, and aging resistance, and have a lower crystallinity, hygroscopicity, and thermal stability. The toughness, transmittance, and aging resistance of CS/PG films are positively correlated with the molecular weight of the branched 1,4-butanediol citrate oligomers. These are due to the fact that the branched 1,4-butanediol citrate oligomer with a high molecular weight could form a stronger hydrogen bond and the more stable cross-linked structure with starch chains than that with a lower molecular weight. The elongation at break of CS/P3G film stored for 3 and 30 d are 98.0 % and 88.1 %, respectively. The mixture of branched butanediol citrate oligomers and glycerol, especially P3/G, has a potential application in the preparation of thermoplastic starch.

Exploring the synergistic effect of carboxymethyl cellulose and chitosan in enhancing thermal stability of polyurethanes through statistical mixture design approach

The thermal stability of polyurethanes, known for its limitations, was addressed in this research by seeking improvement through the introduction of carbohydrate-based chain extenders. In this research paper, we systematically sought to improve the thermal resistance of polyurethanes by incorporating carboxymethyl cellulose and chitosan, representing a pioneering application of the mixture design approach in their preparation. In this synthesis, hydroxyl-terminated polybutadiene and isophorone diisocyanate (IPDI) were reacted to prepare -NCO terminated prepolymer, which was subsequently reacted with varying mole ratios of CMC and CSN to develop a series of five PU samples. The prepared PU samples were characterized using the Fourier-transformed infrared spectroscopic technique. Thermal pyrolysis of PU samples was examined using thermal gravimetric analysis (TGA). It was observed that, among all the samples, PUS-3 showed remarkable thermal stability over a wide temperature range. A comprehensive statistical analysis was conducted to substantiate the experimental findings. It was estimated that CMC and CSN significantly enhance the thermal stability of the samples when involved in an interaction fashion. The ANOVA Table for the mixture design demonstrates that over 90 % of the total variation in thermal stability is explained by the mixture model across a wide temperature range. Moreover, PSU-3 exhibited 4 % more thermal stability over a wide range of temperatures on average, as compared to contemporary samples.

Development of lactic acid based chain extender and soybean oil-derived polyurethanes for ecofriendly sustained drug delivery systems

In the present study, a range of sustainable, biocompatible and biodegradable polyurethanes (PU-1 to PU-4) were synthesized using different combinations of biobased polyol (obtained through the epoxidation of soybean oil, followed by ring opening with ethanol) and polyethylene glycol (PEG) and isophorone diisocyanate. The sustainable chain extender used in this study was synthesized by the esterification of lactic acid with ethylene glycol (EG). The synthesized PU samples were characterized through scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy. Wetting ability and thermal degradation analysis (TGA) of the samples were also studied. Subsequently, these PUs were examined as potential drug delivery systems using Gabapentin as a model drug, which was loaded in the polymer matrix using the solvent evaporation method. The drug release studies were carried out in 0.06 N HCl as a release medium according to the method outlined in the United States Pharmacopeia. The maximum drug release was observed for sample PU-P1, which was found to be 53.0 % after 6 h. Moreover, a comparison of different PU samples revealed a trend wherein the values of drug release were decreased with an increase in the PEG content.

Development of biocompatible aqueous polyurethane dispersions using chitosan and curcumin to improve physicochemical properties of textile surfaces

The present research work aims to synthesize a blend of chitosan (CSN) and curcumin (CRN) based aqueous polyurethane dispersions (CSN-CRN APUDs) for the modification of textile surfaces. A series of anionic CSN-CRN APUDs were prepared by the reaction of isophorone diisocyanate (IPDI) with polyethylene glycol (PEG) and extended with chain extenders (CSN and CRN). Structural characterizations of prepared materials were examined through a fourier transformed infrared (FTIR) spectrophotometer. The performances of coated CSN-CRN APUDs on the colorfastness properties (washing, rubbing and perspiration) and the mechanical properties like tensile strength and tearing strength of plain weaved poly/cellulosic textiles (dyed, printed and white) were examined before and after the application of CSN-CRN APUDs. The findings showed that the mechanical and colorfastness properties of all the CSN-CRN APUDs treated poly/cellulosic textile samples were improved significantly as compared with untreated poly/cellulosic textile samples. The newly synthesized CSN-CRN APUD coating materials are sustainable and greener products, particularly derivatized from bio-resources. These coating materials can be utilized as outstanding eco-friendly substitutes for poly/cellulosic textile coatings for surface modifications.

Fabrication and In Vitro Biological Assay of Thermo-Mechanically Tuned Chitosan Reinforced Polyurethane Composites

The progressive trend of utilizing bioactive materials constitutes diverse materials exhibiting biocompatibility. The innovative aspect of this research is the tuning of the thermo-mechanical behavior of polyurethane (PU) composites with improved biocompatibility for vibrant applications. Polycaprolactone (CAPA) Mn = 2000 g-mol-1 was used as a macrodiol, along with toluene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI), to develop prepolymer chains, which were terminated with 1,4 butane diol (BD). The matrix was reinforced with various concentrations of chitosan (1-5 wt %). Two series of PU composites (PUT/PUH) based on aromatic and aliphatic diisocyanate were prepared by varying the hard segment (HS) ratio from 5 to 30 (wt %). The Fourier-transformed infrared (FTIR) spectroscopy showed the absence of an NCO peak at 1730 cm-1 in order to confirm polymer chain termination. Thermal gravimetric analysis (TGA) showed optimum weight loss up to 500 °C. Dynamic mechanical analysis (DMA) showed the complex modulus (E*) ≥ 200 MPa. The scanning electron microscope (SEM) proved the ordered structure and uniform distribution of chain extender in PU. The hemolytic activities were recorded up to 15.8 ± 1.5% for the PUH series. The optimum values for the inhibition of biofilm formation were recorded as 46.3 ± 1.8% against E. coli and S. aureus (%), which was supported by phase contrast microscopy.

Development of amylopectin based polyurethanes for sustained drug release studies

In this research work, the crosslinked structure of polyurethane has been exploited for sustained drug delivery. Polyurethane composites have been prepared by the reaction of isophorone diisocyanate (IPDI) and polycaprolactone diol (PCL), which were further extended by varying the mole ratios of amylopectin (AMP) and 1,4-butane diol (1,4-BDO) chain extenders. The progress and completion of the reaction of polyurethane (PU) were confirmed using Fourier Transform infrared (FTIR) and nuclear magnetic resonance (¹H NMR) spectroscopic techniques. Gel permeation chromatography (GPC) analysis showed that the molecular weights of prepared polymers were increased with the addition of amylopectin into the PU matrix. The molecular weight of AS-4 (M_w ≈ 99,367) was found threefold as compared to amylopectin-free PU (M_w ≈ 37,968). Thermal degradation analysis was done using thermal gravimetric analysis (TGA) and inferred that AS-5 showed stability up to 600 °C which was the maximum among all PUs because AMP has a large number of -OH units for linking with prepolymer resulting in a more cross-linked structure which improved the thermal stability of the AS-5 sample. The samples prepared with AMP showed less drug release (<53 %) as compared to the PU sample prepared without AMP (AS-1).

Biocompatibility and Hemolytic Activity Studies of Synthesized Alginate-Based Polyurethanes

Many investigators have focused on the development of biocompatible polyurethanes by chemical reaction of functional groups contained in a spacer and introduced in the PU backbone or by a grafting method on graft polymerization of functional groups. In this study, alginate-based polyurethane (PU) composites were synthesized via step-growth polymerization by the reaction of hydroxyl-terminated polybutadiene (HTPB) and hexamethylene diisocyanate (HMDI). The polymer chains were further extended with blends of 1,4-butanediol (1,4-BDO) and alginate (ALG) with different mole ratios. The structures of the prepared PU samples were elucidated with FTIR and 1H NMR spectroscopy. The crystallinity of the prepared samples was evaluated with the help of X-ray diffraction (XRD). The XRD results reveal that the crystallinity of the PU samples increases when the concentration of alginate increases. Thermogravimetric (TGA) results show that samples containing a higher amount of alginate possess higher thermal stability. ALG-based PU composite samples show more biocompatibility and less hemolytic activity. Mechanical properties, contact angle, and water absorption (%) were also greatly affected.

Deaggregation and Crystallization Inhibition by Small Amount of Polymer Addition for a Co-Amorphous Curcumin-Magnolol System

Different from previously reported co-amorphous systems, a co-amorphous curcumin-magnolol (CUR-MAG CM) system, as compared with its crystalline counterparts, exhibited decreased dissolution due to its aggregation during dissolution. The main purpose of the present study is to deaggregate CUR-MAG CM to optimize drug dissolution and explore the deaggregation mechanism involved. Herein, a small amount of polymer (HPMC, HPC, and PVP K30) was co-formulated at 5% (w/w) with CUR-MAG CM as ternary co-amorphous systems. The polymer addition changed the surface properties of CUR-MAG CM including improved water wettability enhanced surface free energy, and hence exerted a deaggregating effect. As a result, the ternary co-amorphous systems showed faster and higher dissolution as compared with crystalline CUR/MAG and CUR-MAG CM. In addition, the nucleation and crystal growth of dissolved CUR and MAG molecules were significantly inhibited by the added polymer, maintaining a supersaturated concentration for a long time. Furthermore, polymer addition increased the T_g of CUR-MAG CM, potentially involving molecular interactions and inhibiting molecular mobility, resulting in enhanced physical stability under 25 °C/60% RH and 40 °C/75% RH conditions. Therefore, this study provides a promising strategy to optimize the dissolution and physical stability of co-amorphous systems by deaggregation and crystallization inhibition via adding small amounts of polymers.

Synthesis and molecular characterization of chitosan/alginate blends based polyurethanes biocomposites

The present work aims to examine the structural properties of polyurethanes bio-composites with mole ratios of alginate and chitosan. For this concern, a two-step reaction mechanism was carried out; in the first step isocyanate (-NCO) terminated pre-polymer was synthesized by the reaction of hexamethylene diisocyanate (HMDI) and hydroxyl-terminated polybutadiene (HTPB). The pre-polymer was further extended with 1,4-butanediol (BDO), chitosan (CS) and alginate (ALG) in the second step. Structural and functional group elucidation was done by using Fourier Transform Infra-red (FT-IR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. The crystallinity of the prepared samples was investigated by using X-ray diffraction (XRD) method, the maximum observed intensity was 7704 a.u. The thermal properties of polyurethane composites were carried out using thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). The TGA results showed that thermal stability of RPU-5 was 20 °C more than RPU-1 at each corresponding degradation temperature. It is observed all physical parameters like crystallinity, glass transition temperature, melting point are much dependent on ratio of chain extenders. Overall, CS based samples along with small amount of ALG showed better thermal properties.

Synthesis and molecular characterization of chitosan/starch blends based polyurethanes

Starch/chitosan modified polyurethanes (PUs) were synthesized by step growth polymerization reaction between -NCO terminated prepolymer and chain extenders (1,4-Butanediol/starch/chitosan). Isophorone diisocyanate (IPDI) was reacted with hydroxyl-terminated polybutadiene (HTPB) to synthesize prepolymer and was further reacted with different moles ratio of starch/chitosan to produced five samples of polyurethane (PU). These samples were characterized by Fourier transformed infrared (FTIR) and Proton nuclear magnetic resonance (¹H NMR) spectroscopy. The surface characterizations of PUs were done by scanning electron microscope (SEM). Thermogravimetric analysis showed that the thermal stability of PUs was higher when the mixture of both natural materials was used at equal amounts. It is concluded that combination of both starch and chitosan are efficient for the synthesis of PUs.