Removal of proteins from natural rubber with urea and its application to continuous processes

We investigated the synthesis of a pH-responsive graft copolymer of natural rubber and 4-vinylpyridine. The grafting reaction was carried out using deproteinized natural rubber (DPNR) latex, with potassium persulfate as a free radical initiator. The pH responsiveness of the graft copolymer was investigated using water swelling and contact angle measurements, and was compared with that of pure DPNR. The graft copolymer was found to become responsive in solution at a pH of around 4. Indigo carmine adsorption studies identified the Langmuir isotherm, suggesting monolayer coverage. The adsorbed indigo carmine, a model anionic drug, and carbon dots, an emerging nanosized fluorophore, could be released from the graft copolymer by lowering the pH of the solution. The graft copolymer was tested as a heavy metal adsorbent, and demonstrated selectivity to copper(II) ions. The graft copolymer of 4-vinylpyridine and DPNR developed in this study is therefore a multifunctional, pH-responsive material with a wide range of potential applications, including sensing and catalysis, as a biomedical material and as an adsorbent.

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“…This suggested a reduction in the proteins of the DPNR latex. This result matched that of previous reports …”

Section: Resultssupporting

confidence: 93%

Multifunctional, pH-responsive graft copolymer prepared from deproteinized natural rubber and 4-vinylpyridine via emulsion polymerization

et al. 2017

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“…In Table , the relatively high total nitrogen content of the U‐DPNR may be partly attributed to traces of residual urea in the sample, as a complete removal of urea can be difficult . Also, some of the surface protein denatured by urea may have remained attached to the rubber particles and this may have contributed to a relatively high final nitrogen level.…”

Section: Resultsmentioning

confidence: 99%

“…Urea treatment and enzymatic treatment are equally effective and can reduce the total nitrogen content of rubber to a lower level than the other treatment methods. However, after a urea treatment, all urea must be removed, or high levels of residual nitrogen may be detected in the treated rubber as urea itself contains nitrogen . Also, the urea treatment does not actually break down proteins, but denatures them so that they are easier to wash away.…”

Section: Introductionmentioning

confidence: 99%

Optimal conditions for deproteinizing natural rubber using immobilized alkaline protease

Junoi

Chisti

Hansupalak

2014

J. Chem. Technol. Biotechnol.

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BACKGROUND: Natural rubber latex contains allergenic proteins. Therefore, processes for deproteinizing the latex are needed. An immobilized enzyme process for deproteinization is reported. An optimal protocol was first developed for immobilizing a protease on cellulose−chitosan composite beads. The beads were then used in developing an optimal deproteinization treatment. The main effects and the interactions of the factors for the two processes were identified using a two-level full factorial experimental design.RESULTS: Under optimal conditions (15% cellulose in beads, immobilizing reaction pH of 9, immobilization period of 24 h), the beads attained the highest specific activity of 1685.3 U g −1 beads. Using these beads, the optimal conditions for deproteinization of the latex were: an enzyme loading of 0.1 parts per hundred of rubber (phr), a sodium dodecyl sulfate concentration of 20 phr, 30 • C, and a treatment period of 12 h. The nitrogen content of the rubber was reduced to 0.012% from an initial value of 0.3%. The enzyme beads were operationally stable and could be reused for at least five cycles. CONCLUSIONS:The optimized treatment effectively deproteinized the natural rubber. The final product was free of peptides. This deproteinization treatment was more effective than the conventional urea-based treatment performed for comparison.

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“…Pembuatan DPNR sebagai bahan baku pembuatan TPNR mengadopsi metode yang dikembangkan oleh Yamamoto, Ngia, Klinklai, Saito, & Kawahara (2008): sebanyak 1.000 ml HANR dituangkan dalam gelas piala, kemudian ditambah dengan 0,1% urea dan diencerkan dengan larutan SDS 1% hingga kadar karet keringnya (K3) menjadi 30%. HANR diinkubasi selama 60 menit disertai pengadukan kecepatan rendah pada suhu ruang, kemudian disentrifugasi.…”

Section: Metode Pembuatan Dpnr Dan Tpnrunclassified

Pengaruh Rasio Karet Alam Terdeproteinisasi dengan Monomer Vinil terhadap Karakteristik Karet Alam Termoplastik

Puspitasari¹,

Budianto²,

Maspanger³

2016

J. Tanaman Industri dan Penyegar

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Chemical modification of natural rubber latex by emulsion graft copolymerization with thermoplastic monomer produces thermoplastic natural rubber (TPNR). Ratio composition of natural rubber to thermoplastic monomer determines the TPNR properties. TPNR has good mechanical properties of natural rubber and high processability of plastic material thus enhancing its application in industry. The research, which was conducted at research laboratory of Indonesian Rubber Research Institute, from June to December 2014, aimed to study the effect of the ratio of deproteinized natural rubber (DPNR) latex to vinyl monomer (VM: methyl methacrylate and styrene) on physical and mechanical properties of TPNR produced from batch graft copolymerization. Batch graft copolymerization was conducted at certain ratios of DPNR latex with methyl methacrylate and styrene (70:30; 60:40; and 50:50) at (65°C, 5 hours), and subsequently at (70°C, 1 hour). The result showed that batch technique tend to cause the formation of homopolymer vinyl which also affected the TPNR properties. Visually, the TPNR had white color, hard and brittle texture yet easier to process as shown by low time and energy consumption during compounding. The ratio of DPNR to VM at 70:30 was regarded as the optimum ratio for its balanced properties between elastomeric material of DPNR and thermoplastic material of VM.

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Removal of proteins from natural rubber with urea and its application to continuous processes

Cited by 39 publications

References 14 publications

Multifunctional, pH-responsive graft copolymer prepared from deproteinized natural rubber and 4-vinylpyridine via emulsion polymerization

Multifunctional, pH-responsive graft copolymer prepared from deproteinized natural rubber and 4-vinylpyridine via emulsion polymerization

Optimal conditions for deproteinizing natural rubber using immobilized alkaline protease

Pengaruh Rasio Karet Alam Terdeproteinisasi dengan Monomer Vinil terhadap Karakteristik Karet Alam Termoplastik

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