scholarly journals Cure efficiency of dodecyl succinic anhydride as a cross-linking agent for elastomer blends based on epoxidized natural rubber

2014 ◽  
Vol 132 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Leno Mascia ◽  
Jane Clarke ◽  
Kiat Seong Ng ◽  
Kok Sien Chua ◽  
Pietro Russo
2015 ◽  
Vol 88 (4) ◽  
pp. 560-573 ◽  
Author(s):  
Leno Mascia ◽  
Pietro Russo ◽  
Letizia Verdolotti ◽  
Jane Clarke ◽  
Marino Lavorgna ◽  
...  

ABSTRACT Pregelled mixes of an epoxidized natural rubber, known as ENR50, containing dodecenyl succinic anhydride (DDSA) as cross-linking agent and dimethyl benzyl amine (DMBA) as catalyst, were cured isothermally at 160 °C, and the progress of the reactions was followed by both thermal analysis (differential scanning calorimetry and thermogravimetric analysis [TGA]) and infrared spectroscopy (Fourier transform near-infrared and attenuated total reflection). The curing reactions were found to be approximately first order for both heat of reaction associated with cross-linking and the disappearance of the epoxy groups, even though the reduction of epoxy group concentration was found to be substantially greater than the amount expected from reactions with the anhydride, because of the formation of large quantities of vicinal OH groups. The TGA data have indicated that the pregelled mixes undergo more extensive anaerobic degradation at higher temperatures than the un–cross-linked elastomer, which is accelerated by the presence of the DMBA catalyst.


2018 ◽  
Vol 51 (5) ◽  
pp. 406-420 ◽  
Author(s):  
Nuttida Srirachya ◽  
Takaomi Kobayashi ◽  
Kumarjyoti Roy ◽  
Kanoktip Boonkerd

In this article, thermoreversible covalent cross-linking of maleated natural rubber (MNR) with glycerol was studied. Firstly, NR was grafted with maleic anhydride using a reactive processing method. The result showed that MNR was successfully obtained without the addition of initiator. The highest grafting was 1.76%. Secondly, the obtained MNR was dissolved in toluene and then mixed with glycerol, which is used in this study as the thermoreversible cross-linking agent. Fourier transform infrared spectra of the casted MNR film mixed with glycerol showed that upon heating, covalent ester cross-links were formed via the reaction of succinic anhydride ring with hydroxyl groups of glycerol. The swelling test indicated that the swelling index (%) decreased with increasing glycerol loading. This indicated that the degree of cross-linking directly depended on the amount of glycerol. The tensile strength and modulus were significantly improved upon increasing the level of cross-linking. The MNR cross-linked with glycerol can be remolded at 150°C more than three times. After remolding, the mechanical properties decreased with increasing recycling round.


2016 ◽  
Vol 89 (3) ◽  
pp. 465-476 ◽  
Author(s):  
Rohani Abu Bakar ◽  
Rosiyah Yahya ◽  
Seng Neon Gan

ABSTRACT The dual functionality of epoxide and unsaturated sites in epoxidized natural rubber (ENR) permits different types of cross-linking reactions. Besides the normal vulcanization via double bonds, alternative cross-linking reactions could take place via ring opening of epoxide groups by dicarboxylic acids and diamines. We investigated the cross-linking reactions of silica-filled ENR50 with fumaric acid. The cross-linking reactions at 160 °C were assessed using a Monsanto rheometer. Supporting evidence of the reactions was provided by Fourier transform infrared spectroscopy (FT-IR), solvent swelling, and differential scanning calorimetry (DSC) analysis. FT-IR showed new absorbance peaks of hydroxyl and ester groups in agreement with the structures expected to form during the reactions between ENR50 and fumaric acid. The increase in cross-links led to a lower percentage of solvent swelling, higher glass transition temperature, and higher torque. Incorporation of silica filler has further increased the torque due to the stiffening effect of the filler. The amorphous silica used in the current work was prepared from rice husk. Leaching of the rice husk with dilute sulfuric acid before the combustion at 600 °C for 2 h led to the production of high-purity amorphous silica (>99% SiO2).


2020 ◽  
Author(s):  
H. K. Abdulkadir ◽  
S. A. Abdul Shukor ◽  
R. Hamzah ◽  
N. Z. Noriman ◽  
Omar S. Dahham ◽  
...  

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.


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