Nanoparticle‐loaded UV‐blocking contact lenses

We have developed a novel approach of incorporating UV‐blocking features into contact lenses by dispersing nanoparticles into the lenses. The nanoparticles are prepared by controlling polymerization dynamics using chain terminating and chain transfer agents. A theoretical model is developed to predict the effect of various formulation parameters on the particle size. This approach can produce UV‐blocking nanoparticles of controlled size below 10 nm in diameter with close to 10% conversion. The model predictions for the mean size are in reasonable agreement with the experimental data. The nanoparticles are cleaned and loaded in silicone hydrogel contact lenses by soaking the lenses in a solution of particles in ethanol and acetone. Lenses loaded with about 6% particles w/w in the hydrated lens block sufficient UV light to be classified as Class 1 blockers. The nanoparticles are retained in the lens during soaking in phosphate buffered saline (PBS) and are stable to sterilization by autoclaving. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42495.     

Agricultural proteins as multifunctional additives in ZnO-free synthetic isoprene rubber vulcanizates

Corn zein and wheat gliadin protein are compounded into synthetic cis-1,4-polyisoprene rubber (IR) and sulfur-cured in a zinc oxide (ZnO)-free system. The curing kinetics and mechanical and morphological properties are compared to a ZnO-activated or carbon black (CB)-reinforced cure system. The proteins provide reversion resistance and reinforcement to IR at filler loadings as low as 1 part per hundred rubber (phr). The zein-IR composites exhibit higher moduli, better filler–matrix adhesion, and less filler agglomeration/migration than gliadin-IR because zein is more chemically compatible with IR. The gliadin-IR composites have a lower percent set and hysteresis, indicating the formation of an elastic restoring gliadin network. Optimal properties are achieved at 2-phr gliadin and 4-phr zein. At gliadin loading >2 phr and zein loading >4 phr, the protein domain size increases and mechanical properties deteriorate. At equal filler loading, property improvements over CB-IR are observed for one or both proteins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48141.     

Taguchi method to optimize the micron and submicron size cenosphere particulates filled E‐glass fiber‐reinforced vinylester composites

In this work, the mechanical and tribological characteristics of E‐glass fiber‐reinforced vinylester composites have been investigated experimentally under dry sliding conditions. The E‐glass fiber‐reinforced vinylester composites with uniform micron and submicron size cenosphere particulates of three different sizes (2 µm, 900 nm, and 400 nm) had been prepared in the laboratory. In this work the effect of parameters such as applied normal load, particulate size, sliding speed, sliding distance and roughness on friction and wear behavior have been carried. A plan of experiments, based on the Taguchi design, was performed to acquire data in a controlled way. An orthogonal array L₂₇ (3¹³) and Analysis of variance (ANOVA) have been applied to investigate the influence of process parameters on the coefficient of friction (COF) and sliding wear behavior of these composites. It was found that the submicron size particulates 400 nm as filler contributed significantly to improve the mechanical properties and wear resistance of the composites. The experimental results indicate that the specific wear rate is greatly influenced by applied normal load and particle size. ANOVA results showed that the applied normal load significantly influence the specific wear rate of cenosphere filled glass fiber‐reinforced vinylester composites. Regression analysis is carried to check the suitability of the prediction equation and modeling of the wear parameters and the typical R² values for COF and specific wear rate are 86.7 and 94.3%, respectively. The scanning electron microscopy are used clarify the experimental in the frictional and wear testing. POLYM. COMPOS., 35:775–787, 2014. © 2013 Society of Plastics Engineers     

Facile synthesis,characterization, and ab-initio DFT simulations of energy efficient NN′ dialkyl 1,4 benzene dicarboxamide monomers recovered from PET bottle waste

Aminolytic chemical recycling is performed for obtaining NN′ diethyl 1,4 benzene dicarboxamide, NN′ dibutyl 1,4 benzene dicarboxamide, and NN′ dihexyl 1,4 benzene dicarboxamide from Polyethylene terephthalate bottle waste. The compounds were characterized through Fourier transform Infrared spectroscopy, Raman spectroscopy, UV–Visible spectroscopy, ¹H NMR, ¹³C NMR, mass spectrometry, and elemental analysis. Thermal properties were also analyzed with the help of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Density Functional Theory (DFT) study has been performed at GGA-BLYP (Becke's and Lee–Yang–Parr) functional using SZ basis set to investigate the vibrational frequencies and physical parameters. Experimental vibrational frequencies were found in good accord with the experimental values. Calorific values of the products have been determined using bomb calorimeter as per standard ASTM D240. The values have been correlated with increment of methylene units from NN′ diethyl BdCA to NN′ dihexyl BdCA using standard molar enthalpies of carbon and hydrogen. SEM and EDX analysis of the char residues after combustion has also been carried out to insight the effect of N-alkyl chain length on calorific values. The calorific values of the recovered compounds are comparable to commercial solid fuels and the compounds may find potential applications in aerospace industry.     

Synthesis,characterization and properties of a castor oil modified biodegradable poly(ester amide) resin

A biodegradable poly(ester amide) resin was synthesized from N,N-bis(2-hydroxy ethyl) fatty amide of castor oil with maleic anhydride, phthalic anhydride and isophthalic acid (100:30:35:35 mole ratio) by the polycondensation process. The fatty amide of the oil was obtained for the first time with 95% yield. The chemical structure of the synthesized resin was characterized by spectroscopic techniques like FTIR, ¹H NMR and ¹³C NMR. Various physical properties such as acid value, saponification value, iodine value, specific gravity and viscosity of the resin were also determined. Further the rheological behavior, studied in the steady shear mode showed shear thinning behavior of the resin. The epoxy cured poly(ester amide) thermoset using poly(amido amine) hardener exhibited better properties than with the cycloaliphatic amine hardener cured system. TGA studies also revealed higher thermal stability of the former system than the latter. In vitro-biodegradation study of the poly(ester amide) thermoset using Pseudomonas aeruginosa and Bacillus subtilus bacteria revealed superior biodegradability of the thermoset using the former bacterial strain. Excellent chemical resistance against various chemical media including alkali was observed for epoxy-poly(amido amine) cured poly(ester amide) resin over epoxy-cycloaliphatic amine one. The epoxy-poly(amido amine) cured poly(ester amide) thermoset thus has the potential to be used as surface coating material.     

Strontium(II) ion uptake on poly(N‐vinyl imidazole)‐based hydrogels

In this article, we report on the extraction of Sr(II) ions from aqueous solution with a series of poly(N‐vinyl imidazole)‐based hydrogels. The hydrogels were synthesized by the crosslinking of N‐vinyl imidazole with four different crosslinkers with γ rays as initiators. The well‐characterized hydrogels were used as Sr(II) sorbents. Sr(II) uptake was determined with a colorimetric method with Rose Bengal anionic dye. Scanning electron microscopy–energy‐dispersive spectroscopy analysis of the Sr(II)‐loaded polymers was recorded to ascertain the uptake of Sr(II) ions. The experimental adsorption values were analyzed with the Freundlich and Temkin equations, and the kinetics of adsorption were investigated with a pseudo‐second‐order sorption kinetic model. The results show that the equilibrium data fit well in the Freundlich isotherm and followed a pseudo‐second‐order kinetic model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Timolol‐imprinted soft contact lenses: Influence of the template: Functional monomer ratio and the hydrogel thickness

Isothermal titration calorimetry (ITC) was used to identify the optimal timolol:functional monomer ratio for preparing soft contact lenses (SCLs) able to sustain drug release. ITC profiles revealed that each timolol molecule required six to eight acrylic acid (AAc) monomers to saturate the binding and that these ratios could be the most suitable for creating imprinted cavities. Various poly(hydroxyethyl methacrylate‐co‐AAc) hydrogels 0.2 and 0.9 mm thick were prepared with timolol:AAc molar ratios ranging from 1 : 6 to 1 : 32 and also in the absence of timolol. The hydrogels were reloaded with timolol by immersion in 0.04, 0.06, 0.08, and 0.10 mM drug solutions. Both imprinted and nonimprinted hydrogels showed a high affinity for the drug because of the presence of AAc. Nevertheless, the 1 : 6 and 1 : 8 imprinted hydrogels loaded less timolol but sustained the release better than the other hydrogels. These differences were explained in terms of the different arrangement of the functional monomers along the network. The imprinting effect was more noticeable in the case of the thinnest hydrogels, where the contribution of the diffusion path to the release rate was smaller. The results obtained prove the interest of ITC for the rational design of drug‐imprinted networks to be used as medicated SCLs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

BUBBLE TEMPERATURES OF THE BINARY MIXTURES OF 1,2-DIMETHYLBENZENE WITH 2-PROPANOL, 1-BUTANOL, 2-BUTANOL, 2-METHYLPROPAN-1-OL AND 2-METHYLPROPAN-2-OL AT 95 kPa

Bubble temperatures at 95 kPa over the entire composition range are measured for the five binary systems formed by 1,2-dimethylbenzene with 2-propanol, 1-butanol, 2-butanol, 2- methylpropan-1-ol, and 2-methylpropan- 2-ol. A Swietoslawski - type ebulliometer was used for the measurements. The composition versus temperature measurements are well represented by the Wilson model.     

Polymers from renewable resources: Kinetics studies of the radiochemical graft copolymerization of styrene onto cellulose extracted from pine needles and the effect of some additives on the grafting parameters in an aqueous medium

In an attempt to develop an alternative to petro‐based polymers, we graft‐copolymerized cellulose isolated from the needles of Pinus roxburghii with styrene in a limited aqueous medium in air by simultaneous irradiation using gamma rays as the initiator. The optimum conditions for obtaining maximum grafting were determined as a function of monomer concentration, total dose of irradiation, and amount of water. Maximum percentage of grafting (P_g; 79.9) was obtained at a total dose of 1.152 × 10⁴ Gy with 1.325 × 10^?4 mol of styrene. The effect of methanol, LiNO₃, Cu(NO₃)₂, Mohr's salt, H₂SO₄, HNO₃, and AcOH on P_g was studied. All the additives were found to decrease graft yield, contrary to some reported studies. Total percentage conversion and rates of polymerization, grafting, and homopolymerization were evaluated. Evidence of grafting was provided by the characterization of cellulose and its graft copolymers by Fourier transform infrared spectroscopy, thermogravimetry, and observation of the swelling behavior in some solvents. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1490–1500, 2002     

Use of novel hydrogels based on modified cellulosics and methacrylamide for separation of metal ions from water systems

Interpenetrating networks (IPNs) based on extracted cellulose and its derivatives such as hydroxypropyl cellulose (HPC), cyanoethylcellulose, hydroxyethylcellulose, hydrazinodeoxycellulose, cellulosephosphate with methacrylamide (MAAm), and N,N‐methylene bisacrylamide were synthesized at reaction conditions evaluated for optimum network yield as a function of irradiation dose, concentrations of monomer and crosslinker, and amount of water. These networks were used in sorption of Fe²⁺, Cu²⁺, and Cr⁶⁺ ions. The networks were further functionlized by means of partial hydrolysis with 0.5N NaOH and metal ion sorption studies were carried out. Appreciable amount of all the three ions was sorbed and partial functionalization of the hydrogels results in selectivity in ion sorption with enhanced affinity for Fe²⁺ ions and total rejection of Cr⁶⁺ ions. These results are of interest for the development of low‐cost technologies based on smart hydrogels. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 667–671, 2002