REMOVING EXTRACTABLE PROTEINS IN NATURAL RUBBER LATEX BY CALCIUM CHLORIDE FROM CHICKEN EGGSHELLS

2011 ◽  
Vol 84 (4) ◽  
pp. 543-564 ◽  
Author(s):  
Nuchnapa Tangboriboon ◽  
Prapapan Phudkrachang ◽  
Ruksapong Kunanuruksapong ◽  
Anuvat Sirivat

Abstract Controlling the level of the extractable protein contents in a natural rubber latex is important to the sensitization of natural rubber latex products users. Allergies caused by latex products cause a serious problem in which the sweat removes proteins and allowing a skin contact causing allergic reactions. Calcium oxide from calcined chicken eggshells at 900 °C for 1 h was dissolved in 2M HCl (CaCl2) and used as the thickening agent in which it can modify the protein structure. The eggshells were characterized by the particle size analysis, the impedance analysis, simultaneous thermal analysis (STA), x-ray diffraction (XRD), and Fourier transform infrared spectra (FTIR). Calcium chloride (CaCl2) interacts with the protein molecules and the solvent ions through the hydrogen bonding and the electrostatic interactions driving the extractable protein toward the film surface. Sodium dodecyl sulphate was used as the stabilizer in the natural rubber latex film formation. The extractable protein contents were measured and determined by the modified Lowry method. The concentrated latex samples were further characterized by FTIR, scanning electron microscope, and XRD and the results were reported here. Moreover, near infrared was used to measure the extractable protein spectra of the concentrated latex compounds in the region of 1100–2500 nm.

2018 ◽  
Vol 777 ◽  
pp. 3-7 ◽  
Author(s):  
Wasan Moopayuk ◽  
Nuchnapa Tangboriboon

Mangosteen peel powder is one of the most important bio-antioxidants. Adding mangosteen peel powder as filler into natural rubber latex compound for latex glove film formation via dipping process can help the green anti-microbial properties. The physical (smoothness and thickness of film) and mechanical properties (tensile strength and elongation at break) of latex film are still good. Therefore, adding mangosteen peel powder into natural rubber latex gloves can reduce the anti-allergic and antimicrobial on the film surface. Mangosteen peel powder ground by rapid mill is fine particle and high surface area 2.4216 m2/g suitable for homogeneous and compatible for adding into natural rubber latex compound. Ceramic hand mold was dipped into the Ca (NO3)2 coagulant only 3 seconds, then dipped into the natural rubber latex compounds added mangosteen peel powder for 15 seconds, withdrawn hand mold slowly, cured in the oven at 120°C for 30 min, then dried at room temperature, and casted it off the hand mold. The obtained natural latex glove films added mangosteen peel powder are smooth, clear, and thin film surface, the highest elongation at break 803.2711 ± 31.6477%, good tensile strength 30.2933 ± 6.0218 MPa, dense film without water leakage, and good contact angle.


2010 ◽  
Vol 78 (2) ◽  
pp. 328-333 ◽  
Author(s):  
Waranya Anancharungsuk ◽  
Duangporn Polpanich ◽  
Kulachart Jangpatarapongsa ◽  
Pramuan Tangboriboonrat

2015 ◽  
Vol 659 ◽  
pp. 500-504
Author(s):  
Jirapornchai Suksaeree ◽  
Wirach Taweepreda ◽  
Wiwat Pichayakorn

This study aimed to improve the efficacy of protein removal from fresh natural rubber latex (NRL) and to decrease the production cost by using surfactant treatment and leaching combination processes. The 0.5-3% anionic surfactants, i.e. sodium dodecyl sulfate or sodium lauryl ether sulfate, nonionic tween80 surfactant, or an amphoteric cocamidopropyl betaine surfactant was used in surfactant treatment process. Moreover, water, aqueous surfactant solutions, and/or 1-5% organic solvents (i.e. ethanol, isopropanol and/or acetone) was then used in leaching process. The fresh NRL was preserved by paraben compounds in the presence of surfactant at ambient temperature for 20-120 minutes, and then centrifuged. This might prevent the skin irritation of deproteinized NRL (DNRL) caused by ammonium stabilizer that normally uses in latex industry. The upper rubber mass was then leached for upto three cycles with leaching solvents, and then finally redispersed in distilled water. The milky-like DNRLs were obtained by these processes. Their dry rubber contents were 41-47% that could be adjusted. Their viscosities were 9-13 centipoises with the pH of 6.04-6.61. The protein residues in these DNRLs were 0.0000-0.3244% which were lower than that of fresh NRL (1.2428%). These indicated the efficacy of studied deproteinization process for 73.90-100.0%. Types and concentrations of surfactant, incubation times, leaching solvents, and cycles of leaching process affected the efficacy of deproteinization process. Moreover, the properties of these dried films were not different from that of fresh NR film. This DNRL could be further used for several applications including medical skin products.


2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Kazi Md Zakir Hossain ◽  
Nashid Sharif ◽  
N. C. Dafader ◽  
M. E. Haque ◽  
A. M. Sarwaruddin Chowdhury

A range of radiation vulcanised natural rubber latex (RVNRL) films were prepared using various concentrations of aqueous extracts of mature Diospyros peregrina fruit, which acted as a cross-linking agent. The surface of the RVNRL films exhibited an aggregated morphology of the rubber hydrocarbon with increasing roughness due to increasing fruit extract contents in the latex. An improvement in tensile strength, tensile modulus, and storage modulus of RVNRL films was observed with the addition of fruit extracts compared to the control film due to their cross-linking effect. The glass transition (Tg) temperature of all the RVNRL films was found to be at around −61.5°C. The films were also observed to be thermally stable up to 325°C, while the maximum decomposition temperature appeared at around 375°C. The incorporation of fruit extracts further revealed a significant influence on increasing the crystallinity, gel content, and physical cross-link density of the RVNRL films.


2011 ◽  
Vol 239-242 ◽  
pp. 1601-1604 ◽  
Author(s):  
Xiao Xue Liao ◽  
Hai Sheng Tan ◽  
Ming Chao Luo ◽  
Bing Tang ◽  
Shuang Quan Liao ◽  
...  

The effects of the ratios of natural rubber latex (NRL)and chloroprene rubber latex(CRL) and the type of compatibilizer on physical and mechanical properties of latex film were researched.The oil resistance of vulcanized latex film was tested. The compatibility of the latex blends was also analyzed by TG/DTG method.The results showed that properties of latex film were best when ratio of NRL/CRL was 75/25. As the CRL content increased, oil resistance of latex film was improved. Epoxidized natural rubber latex improved compatibility of NRL and CRL blends.


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