scholarly journals Degradation, swelling profile, and gel fraction of synthetic coral scaffold incorporated PRP or PRF

2020 ◽  
Vol 874 ◽  
pp. 012001
Author(s):  
Erlina Sih Mahanani ◽  
Maulida Nurlaeli ◽  
Woro Winanti ◽  
Monica Hafzi Azizi ◽  
Hammia Zanzabiela
Keyword(s):  
Gel Fraction ◽  
Coral Scaffold

scholarly journals Dynamic Crosslinking: An Efficient Approach to Fabricate Epoxy Vitrimer

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 919
Author(s):  
Yin Ran ◽  
Ling-Ji Zheng ◽  
Jian-Bing Zeng
Keyword(s):  
Stress Relaxation ◽  
Production Efficiency ◽  
Specific Property ◽  
Sebacic Acid ◽  
Compression Molding ◽  
Diglycidyl Ether ◽  
Self Healing ◽  
Gel Fraction ◽  
A New Technique ◽  
Transesterification Catalyst

Epoxy vitrimers with reprocessability, recyclability, and a self-healing performance have attracted increasingly attention, but are usually fabricated through static curing procedures with a low production efficiency. Herein, we report a new approach to fabricate an epoxy vitrimer by dynamic crosslinking in a torque rheometer, using diglycidyl ether of bisphenol A and sebacic acid as the epoxy resin and curing agent, respectively, in the presence of zinc acetylacetonate as the transesterification catalyst. The optimal condition for fabricating the epoxy vitrimer (EVD) was dynamic crosslinking at 180 °C for ~11 min. A control epoxy vitrimer (EVS) was prepared by static curing at 180 °C for ~11 min. The structure, properties, and stress relaxation of the EVD and EVS were comparatively investigated in detail. The EVS did not cure completely during static curing, as evidenced by the continuously increasing gel fraction when subjected to compression molding. The gel fraction of the EVD did not change with compression molding at the same condition. The physical, mechanical, and stress relaxation properties of the EVD prepared by dynamic crosslinking were comparable to those of the EVS fabricated by static curing, despite small differences in the specific property parameters. This study demonstrated that dynamic crosslinking provides a new technique to efficiently fabricate an epoxy vitrimer.

Effect of Deacetylation on Characterization of pH Stimulus Responsive Chitosan-Acrylamide Hydrogels Using Radiation

2014 ◽  
Vol 896 ◽  
pp. 292-295 ◽  
Author(s):  
Kris Tri Basuki ◽  
Deni Swantomo ◽  
Sigit ◽  
Kartini Megasari
Keyword(s):  
Electric Fields ◽  
Chemical Sensor ◽  
Graft Copolymerization ◽  
X Ray Diffraction ◽  
Grafting Efficiency ◽  
Sensor Material ◽  
Swelling Degree ◽  
Gel Fraction ◽  
Stimulus Responsive ◽  
Acetyl Group

Smart hydrogels which can change their swelling behavior and other properties in response to environmental stimuli such as temperature, pH, solvent composition and electric fields, have attracted great interest as chemical sensor material and controlled release system. The pH stimulus responsive hydrogels were synthesized by gamma-irradiation graft copolymerization of chitosan-acrylamide. In this research the influence of deacetylation process on the hydrogels characterization were investigated by measuring grafting efficiency, gel fraction, swelling degree, and crosslink density. Evidence of grafting was confirmed by FTIR spectroscopy. X-ray diffraction showed reduction in the crystallinity of chitosan with different deacetylation process also after the graft copolymerization reaction. The results showed that decreasing acetyl group of chitosan increase the grafting efficiency, gel fraction and swelling degree. While crystallinity decreased. The hydrogels indicated pH-dependent swelling behaviour.

scholarly journals Chemical and Physical Properties of Cassava Starch–CM-Chitosan–Acrylic Acid Gel Copolymerization by Gamma Irradiation

2014 ◽  
Vol 14 (1) ◽  
pp. 37-42
Author(s):  
Gatot Trimulyadi Rekso
Keyword(s):  
Acrylic Acid ◽  
Irradiation Dose ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Γ Irradiation ◽  
Equilibrium Degree ◽  
Preparation Conditions ◽  
Gel Fraction ◽  
Gelatinized Starch ◽  
Acid Gel

Starch is a renewable natural polymer that can be decomposed easily in the environment and can be modified to various applications such as biomedical, agricultural and pharmaceutical applications. Copolymerization of gelatinized starch–CM-chitosan and acrylic acid (AAc) in aqueous medium using γ-irradiation was carried out. The preparation conditions, such as irradiation dose and AAc concentration were investigated. The copolymers were characterized by FTIR spectroscopy, thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM). The results show that by increasing of irradiation dose the gel fraction increases till the dose of 15 kGy. Above the stating dose the gel fraction decreases. The Equilibrium Degree of Swelling (EDS) value slightly increases with increasing irradiation dose and after dose of 15 kGy is decreasing. The swelling of starch–CM-chitosan–AAc hydro gels reduced as the gel content increases. The results indicated that the optimum condition for obtaining hydro gels with desirable properties was irradiated at dose of 15 kGy. The results indicated that SEM revealed that the higher the dose, the lower the copolymer pore size. The starch–CM-chitosan–AAc copolymers have thermal stability higher than that for starch individually.

scholarly journals Synthesis of Polyvinyl Pirrolidone (PVC) /Κ-Carrageenan Hydrogel Prepared by Gamma Radiation Processing As a Function of Dose and PVP Concentration

2013 ◽  
Vol 13 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Erizal Erizal ◽  
Tjahyono Tjahyono ◽  
Dian PP ◽  
Darmawan Darmawan
Keyword(s):  
Tensile Strength ◽  
Gamma Radiation ◽  
Water Absorption ◽  
Chemical Change ◽  
Wound Dressings ◽  
Water Evaporation ◽  
Radiation Processing ◽  
Elongation At Break ◽  
Gel Fraction ◽  
Radiation Technique

The aim of this research is to prepare a biomaterial to be used in health care. A series of hydrogels based on polyvinyl pyrrolidone (PVP)/κ-Carrageenan (KC) has been prepared by radiation technique. PVP (5-15%) were mixed with ΚC (2%) and irradiated by gamma rays at the doses from 25 kGy to 35 kGy (dose rate 7 kGy/h) at room temperature. The chemical change of hydrogels was characterized using Fourier Transform infra Red (FTIR). Gel fraction, water absorption and water evaporation were determined gravimetrically. Tensile strength and elongation at break was measured using Instron meter. It was found that with the increase irradiation dose and PVP concentration, the gel fraction and tensile strength of hydrogels increase. In contrast the elongation at break and water absorption of hydrogels decrease. The hydrogel of PVP/KC hydrogel produced by gamma radiation can be considered for wound dressings.

Molecular Structure and Macroscopic Properties of Synthetic Cis-Poly(Isoprene)

1974 ◽  
Vol 47 (2) ◽  
pp. 342-356 ◽  
Author(s):  
V. A. Grechanovskii ◽  
I. Ya Poddubnyi ◽  
L. S. Ivanova
Keyword(s):  
Molecular Weight ◽  
Functional Groups ◽  
Chemical Structure ◽  
Sol Gel ◽  
Average Molecular Weight ◽  
Dense Network ◽  
Green Strength ◽  
Gel Fraction ◽  
Rubber Compounds ◽  
Processing Properties

Abstract By changing the sol-gel ratio and the structure of the gel fraction it is possible to obtain various grades of synthetic cis-poly(isoprene) which show promise for different applications in the tire and mechanical rubber goods industries. The processability of commercial SKI-3 rubber (at a given average molecular weight of sol) depends mainly on the structure of the gel fraction. Thus, for example, inferior processing properties of rubber compounds is associated primarily with the presence of tight gel. The content and structure of the gel fraction also significantly affect plasto-elastic properties of raw rubbers, e.g. a low plasticity of raw rubbers owes to the increased content of gel fraction. The reduced green strength of compounds based on SKI—3 rubber is accounted for by its chemical structure. Conventional methods used to change the properties of rubbers (including the variation in molecular weight, molecular weight distribution, branching degree, and variation in the content and structure of gel fraction) cannot be considered to be adequate to tackle the problem of the green strength of SKI—3 black stocks. The way to solve the problem appears to be the introduction of functional groups into the polymer chain at the stage of synthesis or processing. These functional groups should be active as to the formation of labile rubber—carbon black—rubber and/or rubber—rubber bonds. High purity of microstructure is necessary but not sufficient for obtaining the required level of green strength of compounded SKI—3. The gel fractions of SKI—3 rubber yield vulcanizates with a more dense network than the corresponding sol vulcanizates. The temperature dependence of the tensile strength is controlled by the network density of vulcanizates from high cis-1,4 poly(isoprene).

Degradation Control of Collagen by Epigallocatechin-3-O-Gallate

2007 ◽  
Vol 342-343 ◽  
pp. 781-784 ◽  
Author(s):  
Han Hee Cho ◽  
Kazuaki Matsumura ◽  
Naoki Nakajima ◽  
Dong Wook Han ◽  
Sadami Tsutsumi ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Enzymatic Degradation ◽  
Egcg Treatment ◽  
Fibrous Protein ◽  
Gel Fraction ◽  
Tissue Culture Plate ◽  
Enzymatic Degradability ◽  
The Stability ◽  
Proliferation Assays

Stabilization of the fibrous protein collagen is important in biomedical applications. This study investigated the efficacy of degradation control of collagen using (-)-epigallocatechin-3-Ogallate (EGCG). EGCG treatment of collagen in solid state was carried out and collagen sponges produced were characterized by measuring the physicochemical properties such as gel fraction, the enzymatic degradability and cytocompatibility. According to gel fraction, EGCG-treated sponges showed the increase of insolubility compared to intact sponges. It showed that EGCG played a role in a crosslinker of collagen. Through in vitro enzymatic degradation test, EGCG-treated collagen sponges showed significant enhancement of resistance to collagenase in comparison with 25 mM EDC-treated collagen sponges. Also, cell proliferation assays showed that 40 mM EGCG-treated collagen sponges exhibited similar cytocompatibility properties compared with tissue culture plate. In summary, EGCG treatment of collagen sponges increased the stability of collagen. Therefore, crosslinking of collagen based scaffold with EGCG imparted more desirable properties, making it more applicable for use as a scaffold in tissue engineering applications.

Formation of homopolymers, graft copolymers, and gel fraction during polymerization of monomer-polymer systems

2007 ◽  
Vol 49 (4) ◽  
pp. 388-394 ◽  
Author(s):  
I. A. Novakov ◽  
Ya. S. Vygodskii ◽  
M. A. Vaniev ◽  
T. V. Volkova ◽  
V. V. Lukyanichev ◽  
...  
Keyword(s):  
Graft Copolymers ◽  
Polymer Systems ◽  
Gel Fraction

Gel Formation in Natural Rubber Latex: 1. Effect of (NH4)2HPO4 and TMTD/ZnO Additives

2003 ◽  
Vol 76 (5) ◽  
pp. 1177-1184 ◽  
Author(s):  
L. Tarachiwin ◽  
J. T. Sakdapipanich ◽  
Y. Tanaka
Keyword(s):  
Natural Rubber Latex ◽  
Gel Formation ◽  
Rubber Latex ◽  
Tetramethylthiuram Disulfide ◽  
Gel Content ◽  
Gel Fraction ◽  
Initial Stage ◽  
High Ammonia ◽  
Long Time ◽  
Long Storage

Abstract The rubber from commercially obtained high-ammonia latex (commercial HA-latex) increased in gel content significantly after long preservation of the latex with 1.0% w/v tetramethylthiuram disulfide (TMTD) and zinc oxide (ZnO). Deproteinization of the HA-latex did not decrease the gel content. The gel fraction of deproteinized commercial HA-latex (DPHA-latex) was not solubilized by toluene containing 1.0% ethanol, showing that the gel fraction is composed of chemically crosslinked rubber. The addition of (NH4)2HPO4, which is usually added to fresh latex (FL-latex) to remove excess amounts of Mg2+ ions by centrifugation, decreased the gel formation in FL-latex preserved with 0.6 % v/v NH4OH due to the removal of Mg2+ ions. The excess amounts of (NH4)2HPO4 accelerated the gel formation in preserved FL-latex and commercial HA-latex. The addition of 0.1% w/v TMTD/ZnO to preserved FL-latex treated with 5% w/v (NH4)2HPO4 caused an increase of gel content during storage. The gel formation in the commercial HA-latex during long time storage was presumed to be caused by excess amounts of Mg2+ ions, TMTD/ZnO and (NH4)2HPO4. Here, TMTD/ZnO accelerated the gel formation at the initial stage of storage, while (NH4)2HPO4 affected in long storage.

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