In Situ Silica Filled Styrene Grafted Natural Rubber by the Sol-Gel Process

2010 ◽  
Vol 93-94 ◽  
pp. 525-528 ◽  
Author(s):  
Torpong Sittiphan ◽  
Pattarapan Prasassarakich ◽  
Sirilux Poompradub
Keyword(s):  
Natural Rubber ◽  
Reaction Temperature ◽  
Sol Gel ◽  
Cumene Hydroperoxide ◽  
Silica Content ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
In Situ Silica ◽  
Tetraethylene Pentamine

In situ silica filling of styrene grafted natural rubber (ST-g-NR) was carried out by using sol-gel reaction of tetraethoxysilane (TEOS). The effects of concentration of catalyst and reaction temperature on the in situ silica content were investigated. ST-g-NR was synthesized via an emulsion polymerization using cumene hydroperoxide (CHPO) and tetraethylene pentamine (TEPA) as initiators. The synthesized ST-g-NR was characterized by a Fourier Transform Infrared Spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR). The content of in situ silica generated in ST-g-NR matrix was determined by Thermogravimetry Analysis (TGA). In situ silica up to 50 parts per hundred rubbers by weight (phr) was successfully filled in the ST-g-NR matrix. The silica content increased with the increase of n-hexylamine concentration. However, the effect of reaction temperature was insignificant to silica content.

Reinforcing efficiency and compatibilizing effect of sol–gel derived in situ silica for natural rubber/chloroprene rubber blends

RSC Advances ◽  
2014 ◽  
Vol 4 (102) ◽  
pp. 58816-58825 ◽  
Author(s):  
Bharat P. Kapgate ◽  
Chayan Das
Keyword(s):  
Natural Rubber ◽  
Sol Gel ◽  
Rubber Blends ◽  
In Situ Silica ◽  
Chloroprene Rubber ◽  
Compatibilizing Effect

The strong CR/in situ silica interaction causes filler accumulation at the interphase and enhances the compatibility and reinforcement in the NR/CR blend.

FUNCTIONALIZATION OF EPDM RUBBER TOWARD BETTER SILICA DISPERSION AND REINFORCEMENT

2018 ◽  
Vol 92 (2) ◽  
pp. 219-236 ◽  
Author(s):  
Naresh D. Bansod ◽  
Bharat P. Kapgate ◽  
Pradip K. Maji ◽  
Anasuya Bandyopadhyay ◽  
Chayan Das
Keyword(s):  
Maleic Anhydride ◽  
Sol Gel ◽  
Silica Content ◽  
Rubber Matrix ◽  
Epdm Rubber ◽  
In Situ Silica ◽  
Grafted Epdm ◽  
Composite Properties ◽  
Rubber Filler

ABSTRACT Functionalization of non-polar ethylene propylene diene monomer (EPDM) rubber by melt grafting of maleic anhydride (MA) and in situ incorporation of sol–gel derived silica in the MA grafted EPDM has been done to prepare EPDM/silica composites to use dual benefits of both the approaches, which results in adequate rubber–filler compatibility, good filler dispersion, and enhanced composite properties. Controlled growth of silica up to 25 parts per hundred rubber (phr) is carried out with the solution sol–gel process using tetraethoxysilane (TEOS) as a silica precursor. Mechanical and dynamical properties of the composites are found to improve consistently as silica content increases. Furthermore, treatment of maleic anhydride grafted EPDM by γ-aminopropyltrimethoxysilane (γ-APS) results in remarkable improvement in composite properties even at the same silica content. This is attributed to the generation of uniformly dispersed spherically shaped nanosilica throughout the rubber matrix as observed in a transmission electron microscopic (TEM) study. This contributes to enhanced crosslinking density and improved rubber–filler interaction. In fact, the reinforcement effect brought by in situ silica relative to unmodified in situ silica/EPDM composites is found to be much higher than that reported in recent work on EPDM/in situ silica composites even with higher silica loading. The mechanical, rheological, and dynamic mechanical behaviors of all the composites are evaluated and compared in detail.

In situ silica reinforcement of natural rubber by sol–gel process via rubber solution

2009 ◽  
Vol 52 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Benjawan Chaichua ◽  
Pattarapan Prasassarakich ◽  
Sirilux Poompradub
Keyword(s):  
Natural Rubber ◽  
Sol Gel ◽  
In Situ Silica ◽  
Sol Gel Process

Thermosensitive hydrogel for in situ-controlled methotrexate delivery

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 910-920
Author(s):  
Teresa Darlen Carrillo-Castillo ◽  
Antonia Luna-Velasco ◽  
Erasto Armando Zaragoza-Contreras ◽  
Javier Servando Castro-Carmona
Keyword(s):  
Sol Gel ◽  
Proton Nuclear Magnetic Resonance ◽  
Infrared Spectrometry ◽  
Resonance Spectroscopy ◽  
Burst Release ◽  
Thermosensitive Hydrogel ◽  
Weight Analysis ◽  
Poly Ethylene ◽  
Copolymer Assembly

Abstract Methotrexate (MTX) is widely used for the treatment of various types of cancer; however, it has drawbacks such as low solubility, lack of selectivity, premature degradation, and side effects. To solve these weaknesses, a hydrogel with the ability to contain and release MTX under physiological conditions without burst release was synthesized. The hydrogel was fabricated with a poly(ɛ-caprolactone)-b-poly(ethylene glycol)-b-poly(ɛ-caprolactone) (PCL–PEG–PCL) triblock copolymer, synthesized by ring-opening polymerization. The characterizations by proton nuclear magnetic resonance spectroscopy and Fourier-transform infrared spectrometry confirmed the copolymer assembly, whereas the molecular weight analysis validated the PCL2000–PEG1000–PCL2000 structure. The copolymer aqueous solution exhibited sol–gel phase transition at 37°C and injection capacity. The hydrogel supported a load of 1,000 μg MTX·mL−1, showing a gradual and sustained release profile of the drug for 14 days, with a delivery up to 92% at pH 6.7. The cytotoxicity of the MTX-loaded hydrogel was performed by the methyl thiazole tetrazolium assay, showing a mean inhibitory concentration of 50% of MCF-7 cells (IC50) at 43 µg MTX·mL−1.

Natural Rubber/In Situ Silica Nanocomposite of a High Silica Content

2005 ◽  
Vol 34 (5) ◽  
pp. 672-673 ◽  
Author(s):  
Sirilux Poompradub ◽  
Shinzo Kohjiya ◽  
Yuko Ikeda
Keyword(s):  
Natural Rubber ◽  
Silica Content ◽  
In Situ Silica ◽  
High Silica Content ◽  
High Silica ◽  
Silica Nanocomposite

In situ silica reinforcement of methyl methacrylate grafted natural rubber by sol–gel process

2011 ◽  
Vol 58 (2) ◽  
pp. 407-418 ◽  
Author(s):  
Natchamon Watcharakul ◽  
Sirilux Poompradub ◽  
Pattarapan Prasassarakich
Keyword(s):  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Sol Gel ◽  
In Situ Silica ◽  
Sol Gel Process

In Situ Filling of Silica onto “Green” Natural Rubber by the Sol—Gel Process

2001 ◽  
Vol 74 (1) ◽  
pp. 16-27 ◽  
Author(s):  
S. Kohjiya ◽  
K. Murakami ◽  
S. Iio ◽  
T. Tanahashi ◽  
Y. Ikeda
Keyword(s):  
Natural Rubber ◽  
Silica Surface ◽  
Sol Gel ◽  
Renewable Resource ◽  
Crosslinking Density ◽  
Silica Particles ◽  
Rubber Matrix ◽  
In Situ Silica ◽  
Silica Composite

Abstract The sol—gel reaction of tetraethoxysilane produced the fine and well-dispersed in situ silica particles in the “green” natural rubber (NR) matrix before curing. This new method was developed for a NR/silica composite material, and a good reinforcement effect of in situ silica was observed on the NR vulcanizate. The method is expected to be an industrially practical technique. The in situ silica did not much inhibit the accelerated sulfur curing. Thus, it is estimated that the concentration of silanol groups on the in situ silica surface was smaller than those on the conventional silica surface. The silica—silica interaction of in situ silica seems to be weaker to result in better dispersion in the rubber matrix compared with the conventional silica. Atomic force microscopy suggested that the wettability of NR onto in situ silica was higher than that onto conventional silica. The hardness, modulus at 50% elongation and the storage modulus at room temperature of in situ silica-filled NR vulcanizate were smaller than those of conventional silica-filled NR vulcanizate, although the crosslinking density of the former was larger than that of the latter and their silica contents were comparable. These unique characteristics of in situ silica-filled vulcanizate seem to be ascribed to the fine and well-dispersed in situ silica particles in the NR matrix. These observations suggest that NR (a renewable resource)/in situ silica composite has much potential as an ecologically “green” material in the rubber industry.

Enhancing Dispersion of Silica Nanoparticles with Ammonium Laurate Surfactant for Natural Rubber Latex Composites

2019 ◽  
Vol 821 ◽  
pp. 74-80
Author(s):  
Wichudaporn Seangyen ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
Peerapan Dittanet
Keyword(s):  
Natural Rubber ◽  
Silica Nanoparticles ◽  
Sol Gel ◽  
Natural Rubber Latex ◽  
Silica Content ◽  
Rubber Matrix ◽  
Rubber Composites ◽  
Rubber Latex ◽  
Beam Radiation

In-situ silica nanoparticles with ammonium laurate surfactant in natural rubber latex composites were characterized to describe the reinforcement mechanism in enhanced mechanical properties. In-situ sol-gel method was introduced to generate silica nanoparticles in natural rubber latex using a mole ratio of water-to-TEOS of 28.9 stirring at room temperature for 24 hours. The addition and effect of adding ammonium laurate surfactant for enhancing dispersion and compatibility between silica nanoparticles and rubber matrix was also studied. The natural rubber latex was then vulcanized by electron beam radiation at 200 kGy. The silica content in rubber composites made in-situ, was analyzed by TGA, showed an increase from 3.08 phr to 8.92 phr, corresponding to addition of TEOS amounts of 10 phr to 30 phr, respectively. The dispersion of silica nanoparticles in rubber matrix with ammonium laurate surfactant was improved and exhibited less aggregation than rubber composites absent of ammonium laurate surfactant as evidenced by SEM-EDX. The increase of silica content in rubber composites exhibited lower swelling ratio and higher crosslink density when compared with neat natural rubber. Also, the modulus at 100% and 300% strain also increased with increasing silica nanoparticles incorporation in contrast to tensile strength.

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