Retardant Polymer Research Articles

Synthesis of grafted copolymers of cod collagen and acrylamides in the presence of alkylborane – p-quinone system

The graft polymerization of acrylamide and N-isopropylacrylamide onto collagen in the presence of triethylborohexamethylenediamine complex and a number of p-quinones, including benzoquinone, naphthoquinone, 2,5-di-tretbutyl-p-benzoquinone, and duroquinone, was studied. In all cases, p-quinones act as polymerization retarders, reducing monomer conversion. An exception is the graft polymerization of acrylamide onto collagen in the presence of benzoquinone, which acts as a polymerization inhibitor. The proportion of the synthetic fragment in the obtained copolymers is determined by the structure of the monomer and p-quinone. The molecular weight distribution curves contain modes related to unreacted collagen, which differ significantly from those of the initial collagen in terms of intensity. This is related to the formation of a grafted copolymer of cross-linked structure, which cannot be analyzed by gel permeation chromatography. The degradation of copolymers under the action of enzymes was controlled by gel permeation chromatography. Enzymatic hydrolysis of copolymers proceeds slower than that of collagen, which confirms the formation of a copolymer. Following three hours after the onset of hydrolysis, the molecular weight distribution curves contain low-molecular weight modes of collagen and low-intensity modes related to polyacrylamide. The morphology of copolymers differs from that of collagen and polyacrylamides. Cytotoxicity evaluation of copolymers is an important research stage, determining their prospects as the basis of materials for regenerative medicine. An analysis of extracts obtained from the copolymers using culture medium by MTT assay showed a high rank of their toxicity, which can be reduced by dilution of collagen and N-isopropylacrylamide copolymer extracts with aqueous solutions. For the copolymers of collagen and acrylamide, the toxicity is maintained due to the high toxicity of the monomer. Their toxicity can be reduced by extraction of unreacted acrylamide with chloroform.

Optimization In-vitro Evaluation and Scratch Wound Healing Assay of Hexacosane Topical Gel for Wound Healing.

The compounds hexocosane, a sterol hydrocarbon identified in the dichloromethane extract and isolated from marine sponges of the genus Agelas. Hexocosane possesses anti-inflammatory and antioxidant activities that reduce inflammation and oxidative stress, they promote cell proliferation and angiogenesis, facilitating tissue regeneration and repair. This multifaceted approach makes this secondary metabolite a promising candidate for developing advanced wound care therapies that effectively address both infection control and wound healing. On the basis of viscosity, in-vitro release, and skin retention, optimal gel formulations were developed with hexocosane (1%) to achieve the best results. A response surface methodology Box-Behnken design was applied on three factors and three levels [carbopol 940 (1, 1.25 and 1.5%), hydroxypropyl methylcellulose (HPMC) (1,1.5 and 1.2%), and propylene glycol (0–1–1.5% and 1–2%, respectively] using three factors and three levels. In order to assess the spreadability and viscosity, a glass slide and a Brookfield viscometer were used. An assay was conducted to determine how topical gel affects wound healing. The optimization study of the gel formulation, involving variations in adhesive polymer (Carbopol 940), release retarding polymer (HPMC K4M), and penetration enhancer (Surfactant), has identified three noteworthy formulations (F4, F8 & F14). Each formulation is characterized by specific attributes such as viscosity, in-vitro drug release, and skin retention. All samples were found to elicit significant wound healing efficacy as evidenced from the representative photomicrographs. The maximum efficacy was elicited by formulation (F4) with 100 mg drug at the time duration of 36 hours.

Progress in Application of Silane Coupling Agent for Clay Modification to Flame Retardant Polymer.

Polymer composites are widely used in various fields of production and life, and the study of preparing environmentally friendly and flame retardant clay/polymer composites has gradually become a global research hotspot. But how to efficiently surface modify clay and apply it to the field of flame retardant polymers is still a potential challenge. One of the most commonly used surface modification methods is the modification of clay with silane coupling agents. The hydrolysable groups of the silane coupling agent first hydrolyze to generate hydroxyl groups. These hydroxyl groups then undergo a condensation reaction with the hydroxyl groups on the surface of the clay, allowing for organic functional groups to be grafted onto the clay surface. The organic functional groups and polymer matrix react to generate chemical bonds so that the composite material's interface is more closely combined. Thus, the dispersion of clay in the organic polymer material and the compatibility of the two is better, which improves the flame retardant effect of the composite material. This paper introduces the classification of a silane coupling agent and the mechanism and process of silane coupling agent-modified clay, outlines the mechanism of silane coupling agent-modified clay flame retardant polymers, reviews the research results on flame retardant polymers of various clays after surface treatment with silane coupling agents in recent years, and highlights the synergistic flame retardant effect of clay and flame retardant organized by silane coupling agents. Finally, it is found that the current research in the field of silane coupling agent-modified clay in flame retardants is focused on the modification of montmorillonite, sepiolite, attapulgite, and kaolinite by KH-550, KH-560, and KH-570, and the development trends in this field are also prospected.

Formulation and evaluation of Mesalamine mini-tablets in enteric-coated capsule for the treatment of ulcerative colitis using a factorial design approach

The Enteric Capsule Drug Delivery Technology (ECDDT) was designed to enable oral administration while ensuring complete enteric protection and swift release in the upper gastrointestinal (GI) tract, without the need for coatings. Current study used a 32factorial design (Stat-Ease Design Expert v12) to formulate a mini-tablet in an enteric-coated capsule to treat ulcerative colitis utilising ECDDT and mini-tablets. Mesalamine, an amino salicylate, was used as a model drug to study the effects of independent variables like HPMC K4M as a release retarding polymer at 10-20% and Crospovidone as a super disintegrant at 2-5% on in vitro drug release to meet desired Q points of dissolution. higher value of Tmax (10 Hours) and T1/2 (9 Hours) was observed for the Optimized formulation with Cmax value of (35.24 ± 0.45 ng/mL), AUC (0-48) (411.58 ± 1.45 hr.ng/mL) and Ke (0.077 ± 0.010 hr-1) it may be due to delayed release formulation.

Applications of fire retardant polymer composites for improved safety in the industry: a review

Applications of fire retardant polymer composites for improved safety in the industry: a review

Formulation, design, and evaluation of valsartan sodium-sustained-release matrix tablets

The main aim of present work was to formulate and evaluate sustain release matrix tablets of Valsartan, an angiotensin II Receptor type 1 antagonist. Sustain release formulation are those which delivers the drug locally or systemically at a predetermined rate for a fixed period of time. The matrix tablet was prepared by direct compression method using by various concentration of chitosan and sodium alginate with combination of various release retardant polymer. The powder mixtures were subjected to various pre-compression parameters such as angle of repose, bulk density, tapped density and Carr’s index shows satisfactory result and the compressed tablets are evaluated for post-compression parameters such as weight variation, thickness, hardness, friability, drug content, in-vitro dissolution and stability studies. In-vitro dissolution studies were carried out for 24 hours using 0.1N HCl for first 2 hours and pH 6.8 phosphate buffers for 24 hours and the result showed that formulations F4 and F7 showed good dissolution profile to control the drug release respectively. Formulation containing higher concentration of chitosan and sodium alginate along with polymers sustainedthedrugreleasefor theperiodof24hours.The compatibilityof thedrug, polymers and other excipients were determined by FT-IR Spectroscopy. Results showed that the drug was compatible with polymers and other excipients. The release data was fitted to various mathematical models such as Zero-order, First-order, Higuchi equation and Korsmeyer- Peppas model to evaluate the kinetics and the drug release. The drug release followed first order and the mechanism was found to be non-Fickian. The stability studies were carried out for 3 months and result indicates that the selected formulations (F4and F7) were stable.

Flame retardant and bioactive polymer for the finishing of cotton and polyester: synthesis, characterization and application

Flame retardant and bioactive polymer for the finishing of cotton and polyester: synthesis, characterization and application

In-vivo study of Budesonide mini-tablets in enteric coated capsules for the treatment of ulcerative colitis

Budesonide, a corticosteroid, was used as a model drug to study the effects of independent variables like HPMC K4M as a release retarding polymer at 2-6% and Crospovidone as a super disintegrant at 2-5% on in vitro drug release to meet desired Q points of dissolution. Current study used a 32 factorial design (Stat-Ease Design Expert v12) to formulate a mini-tablet in an enteric-coated capsule to treat ulcerative colitis utilising ECDDT and mini-tablets. An in vivo study was conducted in New Zealand rabbits to determine the pharmacokinetic parameters for the optimized formulation (BF4-O). Time vs. plasma concentration plots of the Pure drug and Optimized formulation was observed. Plotted Area under the curve indicates the extent of drug absorption inside the body. Pharmacokinetic analysis of Budesonide pre drug plasma concentration–time data provided the following pharmacokinetic parameters like Cmax value ranging (1.42 ± 2.12 ng/mL), Tmax value (4.0 Hours), AUC value (12.77 ± 0.15 h.ng/mL), Half Life (3.5 Hours) and other pharmacokinetic parameters are depicted. Study demonstrates the variability in pharmacokinetic parameters like Tmax, Cmax, T1/2 (Hours), AUC and Ke. Henceforth, the newly developed Mini-Tablet in Enteric Coated capsule could be utilized clinically for the treatment of Ulcerative Colitis, alternatively with cost-effectiveness.

Combustion Properties of Glove-Box Panel Resins Under Fire Accidents

Contributing to the confinement safety evaluation of glove boxes (GBs) connected to high-efficiency particle air filters for radioactive materials under fire accidents, combustion tests of a flammable polymer, i.e., polymethyl methacrylate (PMMA), and a flame retardant polymer, i.e., polycarbonate (PC), as typical GB panel resins have been conducted with an engineering-scale combustion apparatus. Combustion properties such as the mass loss rate (MLR) and the heat release rate (HRR) of PMMA and PC were investigated in the combustion tests. From our results, the relationships of MLR and HRR to the surface area of the plate type of PMMA and PC were deduced.

Fire and Heat Retardant Polymer Materials and Coatings with Functionally Active Phosphorus–Boron–Nitrogen-Containing Components

Fire and Heat Retardant Polymer Materials and Coatings with Functionally Active Phosphorus–Boron–Nitrogen-Containing Components

Rubber-based phosphaphenanthrene grafted polymer and its application to fabricate flame retardant polycarbonate blend with satisfied comprehensive mechanical properties

Grafting flame retardant groups onto common polymer molecule can be a good strategy to constructing superior flame retardant macromolecules, which provides a promising direction to fabricate fire safety polymer materials with satisfied comprehensive mechanical properties. In this thesis, a rubber-based phosphaphenanthrene grafted polymeric molecule (P-SBS) was synthesized via the grafting reaction of 9, 10-dihydro-9-oxa-10-phenanthrene-10-oxide (DOPO) with thermoplastic styrene-butadiene-styrene copolymer (SBS), and then applied to melt blending with polycarbonate (PC) to form P-SBS/PC blend with sea-island structure. The incorporated P-SBS not only brought PC much higher comprehensive flame retardancy, including higher limited oxygen index, shorter self-extinguishing time, less heat release during burning process, higher-quality char layer structure, and fewer amount of flammable volatile emission; but also endowed it with more satisfied comprehensive mechanical properties, including larger elongation at break, better anti-impact, higher flexural strength, and maintained tensile strength. By analysing burning residue, tracking thermal decomposition volatile emission, and inferring the pyrolysis route of P-SBS, the gas- and condensed-phase flame retardant mechanisms of P-SBS in suppressing the flammability of PC matrix were disclosed. The morphology analysis on the matrix fracture section and the embeded P-SBS particles before and after mechanical fracture, revealed the behavioral mechanism of P-SBS particles in improving the ductility, toughness, and stiffness of PC matrix. This study provides a beneficial reference to superior flame retardant molecule constructing and advanced flame retardant polymer material manufacturing.

Formulation and Evaluation of Floating Microspheres

Gastro-retentive dosage forms have potential for use as controlled- release drug delivery systems. Gastro retentive floating drug delivery systems have a bulk density lower than that of gastric fluids and thus increase residence time of drug in stomach and provide controlled delivery of many drugs. The aim of the present study is formulation and characterization of floating microspheres using model drug. Floating microspheres were prepared by oil-in-water emulsion solvent evaporation technique using ethyl cellulose as release retarding polymers. The floating microspheres were evaluated for percentage yield (%), particle size, drug content, drug entrapment efficiency, in-vitro floating ability and in-vitro drug release studies. The surface morphology of prepared microspheres was characterized by scanning electron microscopy. The microspheres were found to be spherical in shape and porous in nature. Compatibility studies were performed by fourier transform infrared (FTIR) technique. The prepared microspheres showed prolonged drug release of 12 h and remain buoyant for more than 12 h. In-vitro release kinetics were studied in different release kinetics models like zero order, first order model. It was concluded that developed floating microspheres offers a suitable and practical approach for prolonged release of drug over an extended period of time and thus oral bioavailability, efficacy and patient compliance is improved

Post-modification of polyoxanorbornene via sequential “click” reactions for the preparation of flame retardant polymers

Ring-opening metathesis polymerization (ROMP) is a widely applicable method for synthesizing different macromolecular structures due to the diversity of functional groups, and the ROMP system has been widely studied in the literature for the preparation of flame retardant polyoxanorbonene (PONB) derivatives. This work aims to synthesize α-bromo ester functional PONB followed by grafting phosphorus groups by orthogonally sequential “click” reactions onto those PONBs. Thus, phosphorus groups incorporated covalently to the side chain and main chains of PONB by nucleophilic thio-bromo and radical thiol-ene “click” reactions, respectively. The effect of phosphorus content in the synthesized polymers on the thermal stability and decomposition properties was investigated by thermogravimetric analysis (TGA). The TGA tests revealed that char yield increases when phosphorus content increases, illustrating an efficient flame retardancy effect. The heat release peak value of polymers was decreased with increasing phosphorus groups from 67.60 W/g to 47.24 and 43.40 W/g by microscale combustion calorimeter (MCC) measurement, respectively. Additionally, vertical and horizontal burning tests were conducted to determine whether phosphorus-containing PONBs have flame-retardant or self-extinguishing properties. According to the burning tests of polymer solutions-impregnated filter papers, it was noted that phosphorous-containing polymers showed slow ignition and self-extinguishing behavior.

Improving mechanical properties of huntite hydromagnesite reinforced flame retardant polymer composites with calcite and zeolite minerals

AbstractAlthough inorganic minerals used as flame retardants in firefighting are much safer alternative to halogen‐containing ones, it is seen that while they impart non‐flammability, they impair some mechanical properties of polymer composites. In this study, calcite and zeolite minerals, with well‐known incombustibility properties, were used together with huntite hydromagnesite as auxiliary minerals to obtain better mechanical properties. In this context, a synergistic effect was created by adding zeolite and calcite to polymer composite systems containing huntite hydromagnesite, and flame retardant polypropylene matrix composites were produced using a twin screw extruder. The thermal properties of the produced composites were determined by thermogravimetric analysis (TGA). Tensile test was applied to the samples to determine their mechanical properties. Structural and morphological properties were characterized by scanning electron microscopy (SEM) analysis. It was found that with an additive load of 60% by weight, the modulus of elasticity of pure polypropylene was increased from 1215 to 3362 MPa. In addition, by loading zeolite together with huntite hydromagnesite, the maximum tensile strength increased from 15.6 MPa to 22.9 MPa, resulting in an increase of 46.80%. Consequently, the synergistic effect obtained by using zeolite with huntite hydromagnesite improved the mechanical properties of the composite.

Surface modification of MOFs towards flame retardant polymer composites

Methods for modifying the surface structure of MOFs are categorized and flame-retardant effects of various modification techniques are examined, emphasizing the development of MOF surface morphology and its compatibility with the polymer matrix.

Preparation and performance of intumescent water-based coatings with both thermal insulation and flame retardant functions

Functional flame retardant polymer materials are of great strategic relevance in reducing energy consumption in the wake of accelerated advances in materials science. In this paper, boehmite sol was employed to modify the surface of hollow glass microspheres (HGMs), self-designed a new type of intumescent flame retardant with melamine polyphosphate and starch (M-S system), which subsequently achieved synergistic flame retardant effects and produced high-performance water-based HGMs@Al2O3/M-S composite coatings that could be successively manufactured. As revealed from findings, HGMs@Al2O3 retained the fundamental structure and characteristics of HGMs and enhanced the interfacial compatibility with the water-based polymer matrix. The thermal conductivity of 0.097 W/(m·K) was achieved at 7 wt% HGMs@Al2O3, which notably strengthened the fire resistance of the coating when compounded with 20 wt% M-S. HGMs@Al2O3 also acted as a catalyst for carbon formation and achieves self-extinguishing off fire when the LOI value reached 36 % and UL94 passed the V-0 test. The maximum pyrolysis temperature of the HGMs@Al2O3/M-S composite coatings was 410.1 °C. The results of conical calorimetry indicate that the HRR were reduced by 76.9 % and the THR by 83.8 %, the superior smoke suppression performance of the material. FPI and FGI were 0.21 m2s/kW and 3.02 kW/m2/s separately, indicating a significant improvement in the fire performance of the material, with high residual carbon strength. When burned, HGMs@Al2O3 migrates to the surface of the material and acts as a flame retardant. It demonstrates that the material is superior to previous resemble products and has tremendous potential for application and further industrialization.

Formulation and Evaluation of Nifedipine Bilayer Floating Tablets

In the present investigation concern, the formulation and evaluation of bilayer floating tablet of Nifedipine which after an oral administration increase gastric residence time, to increase the bioavailability. Nifedipine is the Calcium channel blocker of the dihydropyridine type which used in angina pectoris and hypertension. It has a half-life of 2-4hours and bioavailability of 45-56%. It is advantageous to formulate bilayer floating tablet of Nifedipine helps to increase bioavailability, reduce dosing frequency, and reach maximum plasma concentration rapidly. Bilayer floating tablets comprised of two layers, immediate and sustain release layers. The immediate release layer is comprised of super disintegrating agent Karaya gum, and sustain release layer comprised of low density release retardant polymers like HPMC K4M and Guar gum; and sodium bicarbonate and citric acid gas generating agents. The prepared powder mixtures were subjected to FT-IR for all interaction. The tablets were prepared by direct compression. First, the powder blends of sustained release layer was pre-compressed and then powder blends of immediate release layer was added. Hardness, friability, drug content, floating lag time, total floating time, swelling index and in-vitro drug release were evaluated. In the present study, it was found that formulation F4 containing HPMC K4M and Guar gum in the ratio of 2:1 showed maximum drug release. The release data were adjusted to various mathematical models such as Higuchi, 1st order and zero order to evaluate the kinetics and mechanisms of the drug release and it was best suited for the Higuchi model. There were no notable changes in stability studies.

Preparation of high‐efficient flame retardant PA6 via DOPO‐ITA initiated ring‐opening polymerization of caprolactam

AbstractIt has been a long‐term challenge to synthesize intrinsically flame retardant polyamide 6 (FRPA6) with high‐molecular weight. In this work, through the ring‐opening polymerization of caprolactam initiated by 9,10‐dihydro‐10‐[2,3‐di(hydroxycarbonyl)propyl]‐10 phosphaphenanthrene‐10‐oxide (DOPO‐ITA), intrinsically flame retardant PA6 with high‐molecular weight was successfully prepared. Its chemical structure, thermal stability, mechanical and combustion properties, as well as the retarding mechanism were thoroughly characterized in detail. The FRPA6 containing 3.0% retardant could achieve a V‐0 rating with an LOI value of 31.2%. An interesting phenomenon was observed during V‐0 tests. The melt drip slowly extended downward to form a long strip after moving fire, which was in favor of its heat release in a short time, thereby effectively prevented it from igniting the cotton. That is, a facile method to prepare intrinsically high‐efficiency fire retardant polymer via ring opening and polycondensation was proposed.

Highly transparent and fire-safe polypropylene carbonate composites via guanidine phosphate hydrogen bonding complexation

It is a challenge all the time to prepare transparent flame retardant polymer composites. In this contribution, a biodegradable carbon dioxide derived copolymer polypropylene carbonate (PPC) has been chosen considering its signality for human environmental protection. Nevertheless, the low glass transition temperature (Tg) of PPC limits its practical applications. Herein, polylactic acid (PLA) and flame retardant guanidine phosphate (GP) were selected to obtain PPC composites by the interaction of intermolecular hydrogen bonds (H-bonds). The properties of PPC/PLA/GP composites were systematically studied. The test results showed that GP can be uniformly dispersed and contributed to the composites with enhanced Tg and flame-retardant properties. As a model system, 3 wt.% of GP enabled the PPC/PLA/GP-3 composites with Tg of 60.0 ℃, UL-94 grade of V-0, limiting oxygen index (LOI) of 30.8 %, and a significant reduction of THR (13 %), pHRR (32 %), and pCO (84 %), respectively. Besides that, the introduction of GP displayed slight influences on the intrinsic transparency nature of PPC/PLA. This study provided a facile approach for solving the bottleneck of PPC for advanced applications.

Insights into Ionic Liquids for Flame Retardant: A Study Based on Bibliometric Mapping

Fire is a typical disaster in the processing industry. Ionic liquids, as a type of green flame retardant, play an important role in process safety. In order to grasp the current research status, hotspots, and frontiers in the field of ionic liquids in flame retardancy, the bibliometric mapping method is applied to study the relevant literature in Web of Science datasets from 2000–2022 in this paper. The results show that the research on ionic liquids in flame retardancy is multidisciplinary and involves some disciplines such as energy science, material science, and environmental protection. Journal of Power Sources, Polymer Degradation and Stability, ACS Applied Materials and Interfaces, and Chemical Engineering Journal are the core journals in the field. The results of keyword co-occurrence indicate that the hotspots of research can be divided into five components: the improvement and application of pure ionic liquids electrolytes, the research of gel polymer electrolytes, applying ionic liquids to enhance the polymer materials’ flame retardancy properties, utilizing ionic liquids and inorganic materials to synergize flame retardant polymers, and using ionic liquids flame retardant to improve material’s multiple properties. The burst terms and time zone diagram’s results point out the combination of computational quantum chemistry to study the flame retardancy mechanism of ionic liquids, the study of fluorinated electrolytes, ionic liquids for smoke suppression, phosphorus-containing ionic liquids for flame retardant, and machine learning-assisted design of ILs flame retardants are the research frontiers and future research trends.