scholarly journals Biodegradation of Polyvinyl Alcohol-Based Binary Composites

2021 ◽  
pp. 111-119
Author(s):  
Lubov N. Studenikina ◽  
Vladimir I. Korchagin ◽  
Lubov V. Popova ◽  
Pavel N. Savvin
Keyword(s):  
Polyvinyl Alcohol ◽  
Porous Structure ◽  
Uniform Distribution ◽  
Polymer Matrix ◽  
Complex Nature ◽  
Soil Environment ◽  
Natural Conditions ◽  
Biochemical Media ◽  
Degree Of Filling ◽  
Reinforcing Filler

The behavior of binary composites (BC) containing polyvinyl alcohol (PVA‑1799) and various amounts of microcellulose (MC) in water and biochemical media (soil, compost, water-silt mixture) is studied. The results of the experiment emphasize the complex nature of the biodegradation of the studied composites under natural conditions. Introduction of microcellulose into the polymer matrix of PVA about 60 vol.% is accompanied by the formation of a porous structure that promotes the penetration of water and components of biochemical media into the volume of the material. At the same time, the uniform distribution of the MC fibers creates the effect of a reinforcing filler and allows you to maintain strength even with prolonged soaking of the BC. The achievement of «zero» strength at exposure in water is observed after 2 days, 14 days, 2 months. for BC with a content of MC 0, 80–60, 40–10 vol.%, respectively. After 6 months of incubation in the soil environment, the index of destruction of composites was 0.89, 0.87, 0.95, 0.96 with a degree of filling with microcellulose of 10, 20,40, 80 vol.%, respectively, while there was a lack of fragmentation of the samples. A method of computer colorometry in the dynamics of biodegradation of polysaccharide-filled thermoplastics is proposed to assess the degree of penetration of components of biochemical media into the volume of the material

scholarly journals The Correlation between Physical Crosslinking and Water-Soluble Drug Release from Chitosan-Based Microparticles

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 455
Author(s):  
Emilia Szymańska ◽  
Katarzyna Woś-Latosi ◽  
Julia Jacyna ◽  
Magdalena Dąbrowska ◽  
Joanna Potaś ◽  
...  
Keyword(s):  
Drug Release ◽  
Polymer Matrix ◽  
Drug Loading ◽  
Water Soluble ◽  
Dissolution Behavior ◽  
Complex Nature ◽  
Prolonged Release ◽  
Scanning Calorimetry ◽  
Burst Effect ◽  
The Impact

Microparticles containing water-soluble zidovudine were prepared by spray-drying using chitosan glutamate and beta-glycerophosphate as an ion crosslinker (CF). The Box–Behnken design was applied to optimize the microparticles in terms of their drug loading and release behavior. Physicochemical studies were undertaken to support the results from dissolution tests and to evaluate the impact of the crosslinking ratio on the microparticles’ characteristics. The zidovudine dissolution behavior had a complex nature which comprised two phases: an initial burst effect followed with a prolonged release stage. The initial drug release, which can be modulated by the crosslinking degree, was primarily governed by the dissolution of the drug crystals located on the microparticles’ surfaces. In turn, the further dissolution stage was related to the drug diffusion from the swollen polymer matrix and was found to correlate with the drug loading. Differential Scanning Calorimetry (DSC) studies revealed the partial incorporation of a non-crystallized drug within the polymer matrix, which correlated with the amount of CF. Although CF influenced the swelling capacity of chitosan glutamate microparticles, surprisingly a higher amount of CF did not impact the time required for 80% of the drug to be released markedly. The formulation with the lowest polymer:CF ratio, 3:1, was selected as optimal, providing satisfactory drug loading and displaying a moderate burst effect within the first 30 min of the study, followed with a prolonged drug release of up to 210 min.

scholarly journals SYNTHESIS OF MAGNESIUM PHOSPHATES IN A POLYMERIC MATRIX

2020 ◽  
pp. 860-867
Author(s):  
Ольга Николаевна Мусская ◽  
Валентина Константиновна Крутько ◽  
Анатолий Иосифович Кулак
Keyword(s):  
Phase Composition ◽  
Polyvinyl Alcohol ◽  
Aqueous Solutions ◽  
Crystallite Size ◽  
Polymer Matrix ◽  
Polymer Films ◽  
Thermal Destruction ◽  
Impurity Phase ◽  
Polymeric Matrix ◽  
Magnesium Phosphates

Изучена зависимость фазового состава наноразмерных фосфатов магния (MgNHPO·6HO, Mg(HPO), MgHPO·3HO, Mg(PO)•22HO) с размером кристаллитов 13-54 нм от условий осаждения из водных растворов в присутствии поливинилового спирта и его смеси с поливинилпирролидоном. В полимерной матрице дополнительно образуется примесная фаза MgOHCl. Наличие средних и двузамещенных фосфатов магния в пленках поливинилового спирта и поливинилового спирта/поливинилпирролида ингибируют их термическую деструкцию. The dependence of the phase composition of nanoscale magnesium phosphates (MgNHPO·6HO, Mg(HPO), MgHPO·3HO, Mg(PO)•22HO) with 13-54 nm crystallite size on the conditions of precipitation from aqueous solutions in the presence of the polyvinyl alcohol and its mixture with polyvinylpyrrolidone was studied. In the polymer matrix an additional impurity phase MgOHCl is formed. The presence of medium and disubstituted magnesium phosphates in polymer films of polyvinyl alcohol and polyvinyl alcohol/polyvinylpyrrolidone inhibit their thermal destruction.

scholarly journals The effect of ultrafine detonation synthesized diamond powder on the properties and structure of PVC-based thermoplastic elastomer

2020 ◽  
pp. 30-32
Author(s):  
E. Yu. Lapkovskaya ◽  
P. O. Sukhodaev ◽  
V. E. Red’kin ◽  
A. I. Lyamkin ◽  
D. V. Ershov
Keyword(s):  
Uniform Distribution ◽  
Polyvinyl Chloride ◽  
Polymer Matrix ◽  
Thermoplastic Elastomer ◽  
Diamond Powder ◽  
Thermoplastic Elastomers ◽  
Strength Characteristics

Samples of thermoplastic elastomers based on polyvinyl chloride (PVC) modified with ultrafine detonation-synthesed (nano) diamonds were obtained. It was found that small additives of nanodiamonds improve the strength characteristics and arrange the structure of PVC. A method that allows obtaining a uniform distribution of nanoparticles in a polymer matrix is proposed.

scholarly journals NANOENCAPSULATION AUGMENTS RELEASE EFFICACY AND GLUCOSE TOLERANCE OF 14-DEOXY, 11, 12-DIDEHYDRO ANDROGRAPHOLIDE LOADED POLYCAPROLACTONE NANOPARTICLES IN STREPTOZOTOCIN-NICOTINAMIDE INDUCED TYPE 2 DIABETES

2017 ◽  
Vol 9 (6) ◽  
pp. 49
Author(s):  
Nagalakshmi K ◽  
Sujatha S.
Keyword(s):  
Glucose Tolerance ◽  
Polyvinyl Alcohol ◽  
Glucose Level ◽  
Polymer Matrix ◽  
Mtt Assay ◽  
Water Soluble ◽  
Tween 20 ◽  
Initial Increase ◽  
Oral Glucose

Objective: This study was designed to study the release efficacy and glucose tolerance of 14-deoxy, 11, 12-didehydroandrographolide loaded polycaprolactone nanoparticles in streptozotocin-nicotinamide induced type 2 diabetes.Methods: Biodegradable polymer based novel drug delivery systems had brought a considerable attention to improve therapeutic efficacy and bioavailability of various drugs. In this study, 14-deoxy-11, 12-didehydroandrographolide (sparingly water soluble) loaded polycaprolactone (nano-DDA) was synthesized using polyvinyl alcohol and tween20 as surfactants. MTT assay was performed to analyse the cytotoxicity of both the formulations on L6 myoblasts. Free DDA and nano-DDA were administered orally to the streptozotocin-nicotinamide induced experimental diabetic rats for 45d. Oral glucose tolerance test (OGTT) was carried out at the end of the study. After one week washout period, animals were administered with free and nano-DDA and release efficacy of DDA from polymer matrix and concentration of glucose were analysed.Results: MTT assay revealed that nano-DDA prepared using tween-20 as a surfactant elicited cytotoxicity towards L6 myoblasts, whereas nano-DDA prepared using polyvinyl alcohol as a surfactant remained non-toxic till 10µM. OGTT studies revealed an initial increase of glucose at 30 min followed by a progressive decrease in the glucose level. In rat plasma, a gradual decrease in glucose level was observed up to 32h (139 mg/dl) for free DDA, whereas nano-DDA exhibited a major decrease in glucose concentration at 32h (115 mg/dl) which continued even after 48h (117 mg/dl).Conclusion: A slow and sustained release of DDA from the polymer matrix substantiated that nanoencapsulation enhanced the oral bioavailability of DDA which resulted in decreasing the concentration of glucose which could be due to the pronounced antihyperglycemic activity of nano-DDA over free DDA.

Analytical Model to Establish the Thermal Conductivity of Porous Structure

2014 ◽  
Vol 69 (1) ◽  
Author(s):  
C. H. Mao ◽  
M. A. Othuman Mydin ◽  
X. B. Que
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Pore Size ◽  
Uniform Distribution ◽  
Analytical Model ◽  
Numerical Study ◽  
Fire Retardant ◽  
Mass Conservation ◽  
Intumescent Coating ◽  
Pore Size Distributions

The presented research paper deals with analytical method to determine the thermal conductivity of porous material (intumescent coating) where the main objective is to assess whether it is possible to treat the voids in intumescent coating as having a uniform diameter. Considering the nature of intumescent coating, the mechanisms of its fire retardant properties are expansion and heat absorption. A predictive model should therefore include prediction of expansion behaviour, energy and mass conservation based on both physical and chemical behaviour, and also thermal conductivity of the coating. A 3-D analytical model will be developed to determine the thermal conductivity of intumescent coating. Finite Element simulations using ABAQUS also will be performed to assess the influence of different pore size distributions. The results of this numerical study indicate that, given the same porosity, the overall thermal conductivity of the porous structure is very close to that with uniform distribution of pores of the dominant size. This strongly suggests that, given the difficulty of obtaining precise pore size distribution, it is reasonable to treat an intumescent coating as having a uniform distribution of pores of the same size.

Uniform High Magnetostrictive Properties of Terfenol-D Composites Prepared by a Dry Process

2011 ◽  
Vol 675-677 ◽  
pp. 1179-1182
Author(s):  
Xu Feng Dong ◽  
Min Qi ◽  
Jin Ping Ou ◽  
Xin Chun Guan
Keyword(s):  
Uniform Distribution ◽  
Polymer Matrix ◽  
Saturation Magnetostriction ◽  
Dry Process ◽  
Wet Process ◽  
Active Particles ◽  
Liquid Polymers ◽  
Length Direction ◽  
Magnetostrictive Composites

Magnetostrictive composites were usually fabricated using a wet process. The settlement of particles in liquid polymers due to the gravity results in the inhomogeneous and low magnetostrictive properties. To solve the problem, magnetostrictive composites were prepared using a dry process, and their properties were tested in this paper. Measurement of magnetostriction on different positions along the length direction of the material indicates the magnetostrictive composites prepared by the dry process present uniform properties due to the uniform distribution of the active particles in the polymer matrix. The saturation magnetostriction and the maximum dynamic magnetostriction of the [1-3] Terfenol-D composites prepared in the study was 1005ppm and 4.08nm/A, respectively, which was larger than the [0-3] ones.

scholarly journals Folic acid-containing nanofibers by simultaneous process for transdermal drug delivery:  preparation, characterization, and in vitro biocompatibility

2020 ◽  
Author(s):  
Fatma Nur Parın ◽  
Çiğdem İnci Aydemir ◽  
Gökçe Taner ◽  
Kenan Yıldırım
Keyword(s):  
Folic Acid ◽  
Polyvinyl Alcohol ◽  
Polymer Matrix ◽  
Matrix Material ◽  
L929 Cell ◽  
Skin Care ◽  
Electrospun Fibers ◽  
Simultaneous Process ◽  
Pva Gel

Abstract Nanofibers with bioactive agents are good candidates for skin-care applications due to high spesific surface area, low density and highly porous structure. In this study, hydrophilic based bioactive nanofibers were produced via an electrospinning and electrospraying simultaneous process. Polyvinyl alcohol (PVA), polyvinyl alcohol-gelatin (PVA-Gel) and polyvinyl alcohol-alginate (PVA-Alg) polymers were used as the matrix material and folic acid (FA) particles were dispersed simultaneously on the surface of these hydrophilic nanofibers. The morphology of the nanofibers (NFs) was uniform and dispersed folic acid particles incorporated into the structure of nanofibers as confirmed by scanning electron microscopy (SEM). Thermal behavior, chemical structure of the composite nanofibers were analyzed/investigated by thermogravimetric analysis (TGA) and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) which showed that no chemical bonding between vitamin and polymers. A controlled release of FA-loaded electrospun fibers were carried out by UV-Vis in vitro study within the 8 hour-period in artificial sweat solutions (acidic media, pH 5,44). The obtained PVA/FA, PVA-Gel/FA and PVA-Alg/FA fibers released 49.6 %, 69.55 % and 50.88 % of the sprayed FA in 8 h, indicating the influence of polymer matrix and polymer-drug interactions, on its release from the polymer matrix. Moreover, biocompatibility of all developed novel NFs was assessed by two different cytotoxicity tests,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and neutral red uptake (NRU) assay in L929 cell lines. In all cases, it is clearly concluded that these new electrospun fibers had fast-release of the vitamin and the hybrid process is suitable for transdermal patch applications, especially for skin-care products. Moreover, it has been proposed nanofiber with folic acid as a patch may prevent the COVID-19. The results of cytotoxicity assays on L929 cell reveal that all prepared NFs have no or slight cell toxicity. PVA and PVA-Gel with/without FA nanofibers seems more biocompatible than PVA-Alg nanofibers.

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