Percentage Of Crosslinker Research Articles

Influence of Initial Film Properties in UVO-Mediated Patterning of an Elastomeric Film Using a TEM Grid.

Ultraviolet irradiation of a cross-linked polydimethylsiloxane (PDMS) Sylgard 184 film in the presence of atmospheric oxygen (UVO) through a bare transmission electron microscope (TEM) sample holding grid is a rather simple and widely utilized technique for creating micropatterned surfaces. The surface oxidation of a Sylgard 184 film due to UVO exposure is associated with densification and the formation of a silica-like surface layer, which under a TEM grid happens only over the exposed areas of the film, resulting in a physicochemical pattern. It is known that the depth (hD) of the features depends on the duration of UVO exposure (tE). In this article, we show for the first time that hD also depends on the initial film thickness (hF) and the cross-linker percentage (CL, ratio of part A to part B) in a Sylgard 184 thin film. We show that for a specific tE, hD progressively decreases with the reduction in hF. On the other hand, hD shows a nonmonotonic dependence with CL, resulting in patterns with maximum depth for CL ≈ 10.0%. We attribute this observation to the combined effect of resistance against the penetration of the propagation front by the rigid substrate as well as stress relaxation within the exposed parts of the film below the propagating front in films with higher CL values leading to the variation of hD. The observation reported here would allow the potential fabrication of polymer films with physicochemical patterns with feature height on demand by a one-step, facile technique.

Synthesis and Characterization of Amine and Aldehyde-Containing Copolymers for Enzymatic Crosslinking of Gelatine.

In tissue engineering (TE), the support structure (scaffold) plays a key role necessary for cell adhesion and proliferation. The protein constituents of the extracellular matrix (ECM), such as collagen, its derivative gelatine, and elastin, are the most attractive materials as possible scaffolds. To improve the modest mechanical properties of gelatine, a strategy consists of crosslinking it, as naturally occurs for collagen, which is stiffened by the oxidative action of lysyl oxidase (LO). Here, a novel protocol to crosslink gelatine has been developed, not using the commonly employed crosslinkers, but based on the formation of imine bonds or on aldolic condensation reactions occurring between gelatine and properly synthesized copolymers containing amine residues via LO-mediated oxidation. Particularly, we first synthesized and characterized an amino butyl styrene monomer (5), its copolymers with dimethylacrylamide (DMAA), and its terpolymer with DMAA and acrylic acid (AA). Three acryloyl amidoamine monomers (11a-c) and their copolymers with DMAA were then prepared. A methacrolein (MA)/DMAA copolymer already possessing the needed aldehyde groups was finally developed to investigate the relevance of LO in the crosslinking process. Oxidation tests of amine copolymers with LO were performed to identify the best substrates to be used in experiments of gelatine reticulation. Copolymers obtained with 5, 11b, and 11c were excellent substrates for LO and were employed with MA/DMAA copolymers in gelatine crosslinking tests in different conditions. Among the amine-containing copolymers, that obtained with 5 (CP5/DMMA-43.1) afforded a material (M21) with the highest crosslinking percentage (71%). Cytotoxicity experiments carried out on two cell lines (IMR-32 and SH SY5Y) with the analogous (P5) of the synthetic constituent of M21 (CP5/DMAA) had evidenced no significant reduction in cell viability, but proliferation promotion, thus establishing the biocompatibility of M21 and the possibility to develop it as a new scaffold for TE, upon further investigations.

RSM optimized chitosan based composite hydrogel for sustained drug delivery applications

Hybrid hydrogels with good biocompatibility have practical applications in the field of drug delivery. However, it remains challenging to formulate the hybrid hydrogels for sustained drug release by regulating their pore size and degradation rates. Herein, a hybrid chitosan-alginate hydrogel (superabsorbent) was synthesized using maleic acid as a cross-linker and acrylamide as a grafting agent. The composite hydrogel exhibited a good swelling percentage of 1246% (at pH 10), analysed using response surface methodology (RSM). The hybrid hydrogel system was hemocompatible as well as biocompatible and utilized for drug delivery applications. Pantoprazole sodium was taken as a model drug and it was loaded in the superabsorbent using the swelling diffusion method. The composite hydrogel showed excellent encapsulation efficiency for pantoprazole sodium (99.74%). The intermolecular interactions between hydrogel and drug were examined using different analytical techniques including XRD (X-Ray Diffraction), FTIR (Fourier transform infrared), SEM (Scanning electron microscope), thermal analysis and EDX (Energy dispersive X-ray) mapping. The swelling percentage of the drug loaded hydrogel under simulated gastrointestinal conditions was recorded as 917.80% (at stomach pH 1.2) and 756.95% (at intestinal pH 7.4) where protonation/deprotonation of the drug in the hydrogel matrix played an important role. In vitro drug release from the drug-loaded hydrogel was sustained up to 10 days and correlated with its swelling tendency, displaying higher release profiles at pH 1.2 (99.69%) than at pH 7.4 (72.16%). The pore volume of hydrogel was tuned varying the cross-linker amount during synthesis. BET (Brunauer-Emmett-Teller) results revealed that the pore volume of the hydrogel varied between 0.01775–0.01327 cm3/g for the cross-linker amount between 0.18–0.26 g, respectively. The impact of various factors including amount of cross-linker, pore volume, and drug loading percentage on drug release at pH 1.2 and 7.4 was studied statistically as well as experimentally and these factors significantly controlled the drug release percentage. The drug release from the hydrogel followed the Makoid-Banakar model with Fickian diffusion mechanism. The synthesized composite chitosan-alginate hydrogel could be a promising candidate for its utilization as a sustained drug delivery system.

Evaluation of Gum Arabic Double-layer Microneedle Patch Containing Sumatriptan for Loading and Transdermal Delivery.

As episodes of acute migraine for migraineurs, a self-treatment that promptly relieves headaches and eliminates the associated symptoms would be optimal. Based on the consideration, a rapidly dissolving double-layer microneedles derived from natural acacia was developed. Under the optimized reaction conditions that was screened out through orthogonal designing test, acacia (GA) was conducted on the ionic crosslinking, a prescribed amount of cross-linking composites was applied to fabricate the double-layer microneedles loaded with sumatriptan at the tip. The mechanical strength and dissolving capability of penetrating pigskin along with in vitro release were measured. The component and content of the resulting compound were determined with FT-IR and thermal analysis, and the bonding state of cross-linker was characterized using X-ray photoelectron spectroscopy. Each needle from the constructed microneedles with the maximal drug loading consisted of the crosslinking acacia of around 10.89 μg and the encapsulated sumatriptan of around 1.821 μg. Apart from the excellent solubility, the formed microneedles possessed enough mechanical stiffness to penetrate the multilayer parafilm. The histological section of the pigskin confirmed the insertion depth of the microneedles could reach 300 ± 28 μm, and the needle bulk in the isolated pigskin could be totally dissolved within 240 s. Franz diffusion study displayed that an almost entire release of the encapsulated drug might be realized within 40 min. The coagulum created from crosslinking was composed of -COOof glucuronic acid in the component of acacia and the added crosslinker to form a double coordination bond, and the crosslinking percentage reached about 13%. The release amount of drug from 12 patches made of the prepared microneedles was comparable to that of subcutaneous injection, providing a new possibility for migraine treatment.

Composition for concentrated powder color with gradient color effect and color matching

A dry coating substance was applied using the powder coating method of dry finishing. The coating substance consists of finely ground resin particles, color pigments, and additional additives for particular purposes like gloss or hardness. Powder coating compositions typically include a thermosetting resin that forms a solid film and one or more pigments. However, they can also be thermoplastic. The requirement to comprehend the characteristics and uses of powder coatings as an alternative to conventional liquid coatings is stated as the difficulty. The article discusses the drawbacks of liquid coatings, including their high VOC emissions and negative environmental effects, as well as the advantages of powder coatings, including their lower environmental impact and less waste.The necessity to investigate and comprehend the potential of powder coatings as an alternative to conventional liquid coatings, as well as to give a thorough evaluation of their features and uses, constitutes the article's overall issue statement. This research has compared several published research papers, referred to those, and concluded to make changes in the existing process such as removing manufacturing process i.e Extrusion, and changes in the composition. It was observed that the existing composition lacks certain properties like Abrasion, Impact and Marking/Mar Resistance, and Chemical Resistance. The salt spray test was ineffective as well. A salt spray test was conducted for 240 Hours with 50 g of sodium chloride per liter of distilled water which was successful in the obtained and new composition. Changes were made in the concentration percentage of resin and crosslinker. A new component called filler, manufactured by Solvay and named it Blanc fixen, was used in the manufacturing process.

Preparation of Sustained Release Formulation of Verapamil Hydrochloride Using Ion Exchange Resins.

The purpose of this investigation was to formulate and evaluate the interaction between cation exchange resins and verapamil hydrochloride. The uptake studies were conducted using the rotating bottle apparatus. The Langmuir-like equation was applied to the experimental data and the maximum drug loading was determined from the Langmuir-like parameters. The drug-resin complexes were evaluated using XRD, SEM, and particle size analysis. Release studies were performed using USP dissolution apparatus 2. The resin with the lowest percentage of cross-linking had the highest uptake capacity. The percent increase in particle size due to complexation was found to be associated with drug loading; the highest drug loading had the highest increase in particle size. The X-ray diffraction patterns of the resins and the drug-resin complexes showed that they were both amorphous. The maximum drug release was approximately 40% when conventional dissolution testing was used. Results showed that sink conditions could not be maintained using conventional dissolution methods. Maximum drug release increased dramatically by increasing the volume of samples withdrawn and fresh dissolution medium added. Excellent correlation was obtained between sample volume and drug release rate with an R-value of 0.988. Particle diffusion-controlled model and film diffusion-controlled model were both applied to the experimental data. The results indicated that the rate-limiting step is the diffusion of the exchanging cations through the liquid film. The modified release formulation was prepared successfully and correlated very well with the USP monograph for verapamil hydrochloride extended release capsules.

Engineering natural based nanocomposite inks via interface interaction for extrusion 3D printing

Nanocomposites and low-viscous materials lack translation in additive manufacturing technologies due to deficiency in rheological requirements and heterogeneity of their preparation. This work proposes the chemical crosslinking between composing phases as a universal approach for mitigating such issues. The model system is composed of amine-functionalized bioactive glass nanoparticles (BGNP) and light-responsive methacrylated bovine serum albumin (BSAMA) which further allows post-print photocrosslinking. The interfacial interaction was conducted by 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide crosslinking agent and N-Hydroxysuccinimide between BGNP-grafted amines and BSAMA's carboxylic groups. Different chemical crosslinking amounts and percentages of BGNP in the nanocomposites were tested. The improved interface interactions increased the elastic and viscous modulus of all formulations. More pronounced increases were found with the highest crosslinking agent amounts (4 % w/v) and BGNP concentrations (10 % w/w). This formulation also displayed the highest Young's modulus of the double-crosslinked construct. All composite formulations could effectively immobilize the BGNP and turn an extremely low viscous material into an appropriate inks for 3d printing technologies, attesting for the systems' tunability. Thus, we describe a versatile methodology which can successfully render tunable and light-responsive nanocomposite inks with homogeneously distributed bioactive fillers. This system can further reproducibly recapitulate phases of other natures, broadening applicability.

Effect of Isocyanate as Cross-linker to Reduce Delamination of Finished Leather for Automotive Seat Cover

This study aims to improve the quality of finished leather for seat covers by knowing the effect of isocyanate as a cross-linker to reduce delamination on the finished leather. Delamination is a condition where the three layers of finish (base coat, medium coat, and top coat) do not stick together, resulting in the lifting of the top coat during the adhesion test. The raw material used in the trial is C60 quality crust dyed cowhide, 1.1 mm to 1.4 mm thick with an area of ± 3 sqft. The stages of the finishing process include semi-finished selection, stacking, spraying (base coat), rest, stacking, roller embossing, rest, milling, stacking, spraying (medium coat, top coat), rest, stacking, laboratory, and measuring. The formulation of the improved seat cover article was carried out by increasing the percentage of cross-linker in the base coat mixture. The production formulation used 2% cross-linker, trial 1 used 3% cross-linker, and trial 2 used 4% cross-linker. The best results are with the addition of 4% cross-linker to reduce delamination and have an adhesion resistance value of 24.5 N. The conclusion is that the greater the addition of cross-linker as much as 4% in the base coat of the article seat cover will reduce delamination, increase thickness from 1.1 mm to 1.2 mm, improve color fastness resistance to a value of 4, and reduce softness value from 3.92 mm to 3.42 mm.

Morphology, chemical reaction mechanism, and cross-linking degree of asphalt binder modified by SBS block co-polymer

Recently, the batch production of styrene–butadienestyrene (SBS) modified asphalt has been realized, but quality control is still in the empirical stage. While the chemical reaction position and the cross-linking degree are unclear, affecting the controlling quality of SBS modified asphalt. Therefore, this study investigated the influence of the reaction conditions and the stabilizer content on the performance and morphology of the SBS modified asphalt. And whether the chemical reaction exists and the chemical reaction position were confirmed by preparing the polystyrene (PS) monomer, polybutadiene(PB) monomer, and SBS modified asphalt with and without stabilizer. Finally, the fluorescence microscope (FM) test, Fourier transformation infrared spectroscopy (FTIR) test and the chemical titration method were used to characterize quantitatively the microstructure changes of SBS modified asphalt. The results show that the reaction conditions greatly influence the performance of SBS modified asphalt. After adding the stabilizer, the phase state of the system changed from the SBS phase as a dispersed phase and the asphalt phase as a continuous phase to the double continuous phase, and the network structure was formed. The chemical reaction has taken place in the PB and SBS modified asphalt, and the PB segment of the SBS polymer participates in the chemical reaction. Furthermore, the degree of cross-linking reaction of SBS modified asphalt is low, and the range of the cross-linking percentage is about 12.3%-14.5%.

Statical Significant Analysis of Hardness of Poly Vinyl Alcohol Crosslinked Glutaraldehyde Using Tukey HSD Method

The non-biodegradable polymer occupying the world leads to many issues concerning global warming and other related problems. Due to these issues, there is a need for biodegradable polymers to overcome these issues. This paper focussed on processing polyvinylalcohol (PVA) crosslinked with glutaraldehyde(GA) and studying the harness of crosslinked polymer. The polyvinylalcohol is crosslinked from 0 to 40 volume percent of glutaraldehyde than post cured immersed in 2 mole of Sulfuric acid (H2SO4) for 24 hours to attain complete crosslinking. The Excel Durometer Shore D Hardness tester was used to determine the hardness of PVA and PVA crosslinked GA polymer composites as per ASTM D2240 standards. The influence of glutaraldehyde crosslinking drastically improves the polymer's hardness by up to 15%, and further marginal changes are found. The Tukey HSD method is used to study the significant level and accomplish the optimum crosslinking percentage. From the Tukey HSD test, it is found that the f value more than 5.35 are high level statically significant.

Synthesis of Vinyl–Trivinyl Acidic Resins for Application in Catalysis: Statistical Study and Site Accessibility Assessment

This study aimed to synthesize sulfonated polymer resins based on styrene and trimethylolpropane triacrylate (TMPTA) and evaluate their catalytic efficiency in glycerol acetylation. A factorial design was used, with two factors, three levels, and three replicates of the center point. The factors were cross-linker percentage (YTMPTA) and cross-linker feed time (TTMPTA). Ion-exchange capacity, swelling index, and catalytic efficiency were analyzed to characterize each resin. Lower cross-linker percentages resulted in higher catalytic efficiencies, as expected. Resins synthesized with 2, 6, and 10% TMPTA had mean catalytic efficiencies of 215, 176, and 121, respectively. A linear correlation was observed between catalytic efficiency and cross-linker percentage, with R2 = 0.9971. Statistical and kinetic models were developed to represent the experimental results and support the development of strategies to improve resin formulation and synthesis conditions. TMPTA feed time at low and high levels positively influenced catalytic efficiency; the result is attributed to the micro- and macrostructure of resins. This finding was corroborated by the kinetic constants provided by the model.

A simple preparation method of rotaxane cross-linker based on γ-cyclodextrin and its application in hydrogel materials

Currently, preparation of rotaxane cross-linker (RC) requires at least two-step or more complex chemical reactions. Therefore, a simple and efficient method is proposed to prepare RC based on γ-Cyclodextrin (γ-CD), which requires only one-step chemical reaction. This means that it is more convenient to apply RC to prepare hydrogels with pulley effect. The structures of RC are characterized by 1 H NMR, 2D NOESY NMR, DOSY NMR, XRD and thermal gravimetric analysis. And the effects of reaction conditions on the yield of RC are studied. RC and traditional cross-linker (N, N’-Methylenebis(acrylamide), MBA) are, respectively, can be copolymerized with acrylamide (AM) to prepare hydrogels to compare the swelling ratios and deformation properties of hydrogels. Furthermore, the effect of mineralization degrees on the swelling ratios of hydrogels and the effect of hydrogels prepared with different content of cross-linker on deformation properties are explored. After absorbing water for 200 h, the swelling ratio of slip-ring hydrogel 0.5% (% is the weight percentage of cross-linker to AM) is 79.05, while that of traditional hydrogel 0.5% is 8.8. The elongation at break of traditional hydrogel 0.6% (211%) is much smaller than that of slip-ring hydrogel 0.6% (6467%) and the compression modulus of traditional hydrogel 0.6% (0.20 MPa) are greater than that of slip-ring hydrogel 0.6% (0.11 MPa). Thus, the swelling ratios and deformation properties of hydrogel prepared by RC are better than that of hydrogel prepared by traditional cross-linker. Lastly, the seepage properties of hydrogel dispersions in porous media are also investigated. The hydrogel dispersion prepared by RC has lower injection pressure and higher residual resistance coefficient than that of traditional cross-linker.

Biodegradable dual-layer Polyhydroxyalkanoate (pha)/Polycaprolactone (pcl) mulch film for agriculture: Preparation and characterization

• Biodegradable dual-layer mulch film based on polyhydroxyalkanoate (PHA) and polycaprolactone (PCL) • Produce mulch film with higher biodegradability without generating microplastics • Use of radiation crosslinking technique to improve the adherence between PHA and PCL • Soil burial test with high degradability percentage for dual-layer mulch film. This study focused on preparing biodegradable dual-layered mulch film based on polyhydroxyalkanoate (PHA) and polycaprolactone (PCL). The main aim of this study is to prepare mulch film with higher biodegradability for rice seed germination. Common plastic mulch films are mostly non-readily biodegradable and stay as residual in soil for a very long duration leading to an increase in salt content and reduction in water and nutrient movement in the soil. This makes the farmland unusable for agricultural purposes. The PHA and PCL were the ideal options as both have their merits and demerits which compensates each other while being cast into double layers and are highly biodegradable. The novelty of this study emphasizes the attachment of PHA and PCL as a dual layer at different ratios that offers a higher bio-degradability percentage. The dual-layer mulch film is made of PHA as the first layer and a mixture of PHA and PCL at different ratios as the second layer. The ratio of PHA/PCL used was 90:10, 70:30, and 50:50. The dual-layered mulch film was prepared using the hot-press technique and later cross-linked by using electron beam irradiation in order to ensure the strong adherence between the two layers. The gel content analysis was performed to measure the crosslinking percentage. The radiation dose of 30 kGy was chosen as the minimum amount of crosslinking and approximately 3.00% was attained for the course. The mixture of PHA/PCL films with different ratios, PHA and PCL virgin film were subjected to a soil burial bio-degradability test. The PHA and PCL virgin film had shown the highest degradation percentage, almost 48.34% just in five weeks. Further characterization was performed on virgin dual-layered PHA/PCL (100%) based on their higher degradability tendency. The apparent properties, morphology, thermal stability, chemical composition, and mechanical properties of dual-layer PHA/PCL (100%) were tested thoroughly. The thickness and transparency attained for dual-layer PHA/PCL (100%) were around 175.25μm and 110.45%. The thermal properties of both single layer PHA and PCL showed good stability, Meanwhile, the virgin dual-layered PHA/PCL mulch film had shown a poor thermal stability. The peak positioning in FTIR for single layer PHA and PCL at 3042.37cm −1 , 2942.37cm −1 , 1719.54cm −1 ,1453.33cm −1 ,1378.95cm −1 and 1181.48cm −1 remained unchanged in virgin double-layered PHA/PCL film as well. The outcome of the analyses clearly indicates the possibilities of the dual-layer PHA/PCL (100%) with greater bio-degradability. The soil burial biodegradability test needs to be prolonged up to its full potential. The other characteristics such as water permeability, photo permeability, crystallinity, and heat preservation need to be investigated as well.

Boron Nitride-Doped Polyphenylenic Organogels.

Herein, we describe the synthesis of the first boron nitride-doped polyphenylenic material obtained through a [4 + 2] cycloaddition reaction between a triethynyl borazine unit and a biscyclopentadienone derivative, which undergoes organogel formation in chlorinated solvents (the critical jellification concentration is 4% w/w in CHCl3). The polymer has been characterized extensively by Fourier-transform infrared spectroscopy, solid-state 13C NMR, solid-state 11B NMR, and by comparison with the isolated monomeric unit. Furthermore, the polymer gels formed in chlorinated solvents have been thoroughly characterized and studied, showing rheological properties comparable to those of polyacrylamide gels with a low crosslinker percentage. Given the thermal and chemical stability, the material was studied as a potential support for solid-state electrolytes. showing properties comparable to those of polyethylene glycol-based electrolytes, thus presenting great potential for the application of this new class of material in lithium-ion batteries.

Study of nano cellulose-based membrane tailorable biodegradability for use in the packaging application of electronic devices

With a growing demand for packaging materials and witnessing many landfills and huge garbage islands floating in the Pacific oceans, the need for an alternative material such as bio-degradable plastics has risen. Cellulose-based materials are already in use in several packaging industries. Nanocellulose, a processed cellulose with a specific nanostructure, have several advantages such as high specific strength, modulus, high surface area and unique optical properties. By varying the crosslinking percentages, the kinetics of degradation can be tailored. In this work, extracted cellulose from sugarcane bagasse was hydrolyzed to obtain nanocellulose, which was used to fabricate packaging films (membrane) with PVA as matrix and nanocellulose. Variations of PVA and nanocellulose loadings, and crosslinking agent ratios. In the fabricated films were investigated for chemical, mechanical, optical, thermal, and topographical properties. Results from the degradation tests under appropriate physically simulated environments have suggested that the crosslinking has enhanced the mechanical properties, extent of degradation was dependent on percentages of crosslinking. A real-world device packaging application was demonstrated by encapsulation of perovskite solar cells with the fabricated nanocellulose film revealed that the lifetime of the devices improved which might be indicative of the film having lower permeability for oxygen and moisture.

Design of smart nanodevices based on N‐vinyl caprolactam nanogels for photosensitizers

AbstractSmart PVCL‐based nanogels for photosensitizers were prepared following the thermo precipitation methodology. PVCL‐based imprinted and non‐imprinted NGs are reported with different percentages of N,N′‐methylenebisacrylamide (BIS) as crosslinker agent. Zn(II)phthalocyanine (ZnPc) is employed as a model photosensitizer and incorporated as a template molecule for imprinted NGs or it loads post‐synthesis for non‐imprinted NGs. In order to analyze the chemical structure, NGs were characterized using infrared microscopy. Hydrodynamic diameter was determined by dynamic light scattering. The phase transition temperature was measured by UV–vis spectroscopy. The phase transition temperature and Dh values were regulated by the percentage of crosslinker and the presence of the photosensitizer as a template or post‐synthesis load. In all cases, the yields were acceptable and the smart nanodevices were stable.

In Vitro Investigation and Characterization of Silicone Matrix IVR Loaded with Levonorgestrel: A Propper Method for Hormon Replacement Therapy

Introduction: Among 3 to 30 percent of women of reproductive age, experience abnormal uterine bleeding (AUB). Vaginal rings are one of the systems of interest for the local delivery of hormones that due to their polymeric structure allow prolonged release of drug. In this study, the design and fabrication of matrix vaginal rings containing levonorgestrel (LNG) were investigated.
 Methods: In this experimental study, at first, two pieces of aluminum mold were designed, then base (A) and cross-linker parts (B) of polymer with LNG were mixed and 48 polymeric rings containing LNG were manufactured by injection molding method. To achieve the desired drug release values in a given time, the effect of temperature, rpm, release environment, different initial loading, cross-linker percentage and a mathematical model to predict release and swelling test were investigated.
 Results: As a result of the experiments, it was revealed that with increasing drug loading, the release rate rises, while increasing the cross-linker percentage reduced the drug release. Finally, the ring A:B=100:9.5 with an initial loading of 0.2 % LNG relative to silicon was selected as an appropriate ring, and release experiments were performed at 37 °C, shaker speed of 80 rpm, and release medium containing 10 % ethanol. Drug release values were measured by spectrophotometer and analyzed by SPSS statistical software version 16.
 Conclusion: Based on the results, it can be deduced that matrix vaginal ring containing LNG is a suitable drug delivery system for prolonged release of LNG for treatment of AUB that depending on the drug initial loading and cross-linker percentage, the required diffusion coefficient, and release rate can be achieved in a certain time.

Spider silks mechanics: Predicting humidity and temperature effects

We deduce a microstructure inspired model for humidity and temperature effects on the mechanical response of spider silks, modeled as a composite material with a hard crystalline and a soft amorphous region. Water molecules decrease the percentage of crosslinks in the softer region inducing a variation of natural length of the macromolecules. The resulting kinematic incompatibility between the regions crucially influences the final mechanical response. We demonstrate the predictivity of the model by quantitatively reproducing the experimentally observed behavior.

UV Radiation Crosslinking of Acrylated Palm Olein (APO) Copolymer Resins for 3D Printing

Generally, only a few especially acrylic monomers have photoabsorption characteristics to allow for effective stereolithography (STL) to take place. Biomaterial product from palm oil, Acrylated Palm Olein (APO), is seen as an ideal alternative to petroleum-based polymers due the diminishing petrochemical supply and abundant of the natural polymer in the market. In this study, APO as a biopolymer is introduced to synthetic polymers Polyethylene Glycol Dimethylacrylate (PEGDMA) and Polyethylene Glycol Diacrylate (PEGDA), separately. All three polymers offer photoabsorption characteristics that enable them to be the resins for ultraviolet (UV) 3D printing. The crosslinking of both copolymers is optimized by comparing two different UV radiation techniques; UV cured machine and UV STL 3D printer. The degree of crosslinking for both APO-co-PEGDMA and APO-co-PEGDA through gel fraction analysis are studied and compared with their prepolymer resins. As predicted, the maximum degree of crosslinking of APO-co-PEGDMA and APO-co-PEGDA samples are achieved from the fabrication of samples by 3D printing and recorded at 67.50% and 59.50% respectively, comparing to the samples cured by UV cure machine, which recorded maximum crosslinking percentage at only 21.31%. Further analysis is done using swelling test to study water absorption capacities of copolymers and results shows that APO-co-PEGDMA able to retain water at maximum of 42.47% and APO-co-PEGDA at 52.02% from the 3D printed samples, and recorded lowest readings at 22.82% and 25.56% respectively. UV cured samples are recorded to have lowest readings at 3.89% for APO-co-PEGDMA, and 4.23% for APO-co-PEGDA. Fourier Transform Infrared (FTIR) Spectroscopy confirmed the successful crosslinked of the copolymers. Analysis of FTIR shows that there are presence of new peaks and shifting of peaks, indicating that APO is crosslinked with PEGDMA backbone as well as PEGDA backbone. These also suggest that both polymers are suitable to be incorporated with APO as new photopolymer resins, fabricated using UV radiation crosslinking, with PEGDMA shown a slightly better result. All results are agreeable with FTIR results.

Crosslinking effect on polyvinyl alcohol resin for barrier properties of barrier biaxial orientation films

A novel barrier chemical coating was formulated and developed by using an organic and inorganic sol-gel process. In this work, a hybrid solution was prepared using different percentages of cross-linker into a polyvinyl alcohol and Tetraethyl orthosilicate to improve the barrier properties of biaxial oriented polypropylene (BOPP) films. The TGA results showed that thermal stability had been enhanced after incorporating tetraethyl orthosilicate as inorganic materials. The transparency of coated films showed enhanced e.g. haze percentage, which improved about 12% and gloss properties were for 90 GU. The coated side and plain side COF were measured at about 0.4, COF is an important slip property at the end-use application. After coating, printing properties were checked and found that the thickness and particle size of pigment were uniform and color strength was also suitable for the packaging applications. The oxygen transmission rate (OTR) properties have been improved from 1880 cc/m2/day to 0.9 cc/m2/day compared to a plain film. The water vapor transmission rate (WVTR) properties have been improved from 10 g/m2/day to 5.9 g/m2/day a plain film. The application of the films showed an excellent barrier for bread packed in coated film and checked for nine days. The results showed that micro-organism was reduced by enhancing the barrier properties by applying the coating on film.