Abstract
For a long time, skim latex has been regarded as waste from the latex centrifugation process. To recover the rubber, skim latex is coagulated using strong acid due to the high presence of non-rubbers, resulting in products of low quality and unpleasant odour. Additionally, the acid discharged into effluent ponds causes malodour and adversely affects the health of nearby residents. Considering this, a novel method employing a membrane filtration system was utilised, successfully recovering and concentrating skim latex while removing water-soluble non-rubbers. The resulting latex concentrate was then compared to raw skim latex in terms of latex, colloidal, and film properties. Latex properties, namely total solids content (TSC), dry rubber content (DRC), alkalinity, nitrogen content, and gel content were determined. For the colloidal properties, particle size and distribution, zeta potential, and rheological properties (flow and viscoelastic behaviours), were characterised. The film properties assessed included the swelling index, appearance, and tensile properties. Significant improvements in latex properties after concentrating were observed, with both TSC and DRC increasing to 42% and 36%, respectively, while alkalinity, nitrogen, and gel contents decreased to 0.61%, 2.23%, and 54%, respectively. Particle size distribution in raw skim latex (RSL) exhibited a tri-modal distribution, but after membrane filtration, concentrated skim latex (CSL) showed a bi-modal distribution with particle sizes ranging from 0.03 to 0.3 µm and 0.3 to 5 µm and average sizes of 0.07 and 1 µm, respectively. Changes were also noted in zeta potential and rheological behaviour after membrane filtration. The isoelectric point of zeta potential shifted to a higher pH, from 4.2 for RSL to 4.9 for CSL, and the absolute zeta potential values decreased with increasing pH values. CSL also demonstrated a different flow behaviour, fitting well to the Herschel-Bulkley model, unlike RSL, which conformed to the Bingham model. Membrane concentration resulted in significant increases in CSL yield stress, consistency index, and shear thinning behaviour, leading to higher moduli values and indicating increased interaction between CSL particles. Conversely, CSL films prepared via casting swelled more in toluene, approximately two times more than RSL films. Nevertheless, RSL films were more opaque and only became transparent after leaching, indicating high non-rubber contents. Regarding tensile properties, both unleached and leached CSL films exhibited a similar tensile versus elongation profile, with ultimate tensile strength and elongation at break values ranging between 1.4 and 1.6 MPa and 650 and 700%, respectively.
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The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
References
Lim HM, Misni M (2016) Colloidal and rheological properties of natural rubber latex concentrate. Appl Rheol 26(1):25–34
Gomez JB, Moir GFJ (1979) The ultracytology of latex vessels in hevea brasiliensis. MRRDB Monograph No 4:1–18
Yeang HY, Esah Y, Samsidah H (1995) Characterisation of zone 1 and zone 2 rubber particles in Hevea brasiliensis latex. J Nat Rubb Res 10(2):108–123
Nawamawat K, Sakdapipanich JT, Ho CC, Ma Y, Song J (2011) Surface nanostructure of Hevea brasiliensis natural rubber latex particles. Colloids Surfaces A Physisochem Eng Aspects 390:157–166
McGavack J (1959) The preservation and concentration of Hevea Latex. Rubber Chem Technol 32(5):1660–1674
Yeang HY, Esah Y, Samsidar H (1995) Characterisation of zone 1 and zone 2 rubber particles in Hevea brasiliensis latex. J Nat Rubb Res 10(2):108–123
Subramaniam A (1980) Molecular weight and molecular weight distribution of natural rubber. RRIM Technol Bull 4:1–24
Baker HC (1958) Rubber from centrifuged skim latex. Rubber Develop 11(1):2–8
Veerasamy D, Nik Ismail NI, Mohd Nor Z (2013) New materials from concentrated skim latex. MRB Rubber Technol Dev 13(2):6–13
Lau CM, Subramaniam A (1989) Recovery and applications of waste solids from natural rubber latex serum. Proc Rubb Growers Conference Malacca Kuala Lumpur 23:525–547
Smith MG (1969) Recent aspects of block natural rubber production by mechanical methods. J Rubb Res Inst Malaysa 22(1):78–86
Bristow GM (1990) Composition and cure behaviour of skim block natural rubber. Nat Rubb Res 5(2):114–134
Morris JE (1954) Improved rubbers by the enzymatic deproteinisation of skim latex. In: Proceedings of the 3rd Rubber technology Conference, London 13–37
George KM, Alex R, Joseph S, Thomas KT (2009) Characterization of enzyme-deproteinized skim rubber. J Appl Polym Sci 114:3319–3324
Sethu S, Subbiah RM (1973) Deammoniation of skim latex using a new desorption column. Proc Rubb Res Inst Malaysia Plrs Conf 1973:381–385
Ab Kadir Bakti N (1990) Ammonia stripping from skim latex using the baffle-plate and rotating-blade counter-current colums. In: The 6th Symposium of Malaysian Chemical Engineers, University Technology Malaysia, Kuala Lumpur, 4 – 5 June 1990:IAP-1 – IAP-13
Khoo TC, Ong CO, Rais AR (1991) A new process for skim rubber production. Proceedings RRIM Rubber Growers’ Conference 1991:495–510
Ng CS (1983) Quaternary ammonium surfactants as alternative coagulants of skim latex – A laboratory study. J Rubb Res Inst Malaysia 31(1):49–59
Danwanichakul D, Rattanaphan O, Srisatjang J, Danwanichakul D (2014) Extraction of protein from skim natural rubber latex using PEG as a surfactant via low speed centrifugation and continuous flow. J Appl Poly Sci 131(4):39900–39908
Than-ardna B, Tamura H, Furuike T (2019) Improving deproteinized skim natural rubber latex with a further leaching process. Eng Appl Sci Res 46(1):64–71
Sakdapipanich JT, Nawamawati K, Tanaka Y (2002) Recovery of deproteinised small rubber particles from skim natural rubber latex: Effect of some inorganic salts. J Rubb Res 5(1):1–10
Sethu S (1964) Ion-exchange membranes. Application to the treatment of natural rubber skim latex. J Appl Polym Sci 8:2249–2259
Devaraj V, Zairossani M, Pretibaa S, Aimi I (2012) An ultrafiltration system for concentration of latices and a process utilizing the system. Malaysian Patent Application No. PI 2012004868
Devaraj V, Zairossani MN, Pretibaa S (2006) membrane separation as a cleaner processing technology for natural raw rubber processing. J Appl Membrane Sci Technol 4:13–22
Veerasamy D, Supurmaniam A, Nor ZM (2009) Evaluating the use of in-situ ultrasonication to reduce fouling during natural rubber skim latex (waste latex) recovery by ultrafiltration. Desalination 236:202–207
Devaraj V, Zairossani MN (2013) Environmentally friendly latices processing by ultrafiltration membrane system. Proceedings of Smithers RAPRA ‘Latex 2013 and Synthetic Polymer Dispersions, Kuala Lumpur, 10–11 September 2013
ISO (2014) ISO 124 latex, rubber – Determination of total solids content
ISO (2005) ISO 126 natural rubber latex concentrate – Determination of dry rubber content
ISO (2011) ISO 125 Natural rubber latex concentrate – Determination of alkalinity
Hunter RJ (1981) Zeta potential in colloid science:principles and applications. Academic Press, London
ISO (2011) ISO 37 Rubber, vulcanized or thermoplastic – Determination of tensile stress-strain properties
Joseph R (2013) Practical Guide to Latex Technology. Smithers Rapra Technology Ltd, United Kingdom
Bozzola JJ, Russell LD (1992) Electron Microscopy: Principles and techniques for biologist. Jones and Bartlett Publishers, Boston
Yusof NH, Manroshan S, Mohd Rasdi FR, Tan KS (2022) Properties of concentrated skim rubber latex using membrane separation process and its comparison with other natural rubber latexes. J Rubb Res. https://doi.org/10.1007/s42464-022-00189-w
Hasma H (1992) Proteins of natural rubber latex concentrate. J Nat Rubb Res 7(2):102–112
Hasma H, Amir Hashim MY (1997) Changes to NR latex proteins on processing the latex to its products. J Nat Rubb Res 12(1):21–32
Bingham EC (1922) Fluidity and plasticity. McGraw-Hill, New York
Herschel WH, Bulkley R (1926) Measurement of consistency as applied to rubber-benzene solutions. Proc Am Soc Test Mater 26:621–633
Barnes HA, Hutton JF, Walters K (1993) An introduction to rheology. Rheology series,3. Elsevier Science Publishers, The Netherlands
Bjӧrn A, De La Monja PS, Karlsson, Ejlertsson J, Svensson BH (2012) Chapter 3. Rheological characterization. In: Biogas. Edited by Kumar S. IntechOpen Limited, London UK
Quemada D (1998) Rheological modeling of complex fluids. I. The concept of effective volume fraction revisited. Eur Phys J AP 1:119–127
Pestridge C, Tadros ThF (1988) Rheological investigation of depletion flocculation of concentrated sterically stabilized polystyrene latex dispersions. Coll Surf 31:325–346
Manroshan S (2018) The colloidal properties of commercial natural rubber latex concentrates. J Rubb Res 21(2):119–134
Mardina V, Yusof F (2018) Skim latex serum as an alternative nutrition for microbial growth. In: Amid A, Sulaiman S, Jimat D, Azmin N (eds) Multifaceted protocol in biotechnology. Springer, Singapore. https://doi.org/10.1007/978-981-13-2257-0_15
Hasma H, Subramaniam A (1986) Composition of lipids in latex of Hevea brasiliensis clone RRIM 501. J Nat Rubb Res 1(1):30–40
Manroshan S, Azhar ME, Baharin A (2020) Effect of maillard reaction in ammonia preserved natural rubber latex using reducing sugars. J Rubb Res 23:365–374
Acknowledgements
The authors express their sincere gratitude to the Director General of Malaysian Rubber Board for granting permission to publish this paper. The invaluable assistance rendered by Hishamudin Samat in preparing the skim latex concentrate and to Fauziah Jalani for her expertise in characterising the latex, colloidal and physical properties of the latexes are highly appreciated. The authors also wish to acknowledge Veronica Charlotte for language editing. This research was supported by funding from the Malaysian Rubber Board Internal Grant 758 (2021).
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Jaswan Singh, M., Yusof, N.H. & Mohd Rasdi, F.R. Latex, colloidal and film properties of concentrated skim latex prepared using membrane filtration process. J Rubber Res (2024). https://doi.org/10.1007/s42464-024-00251-9
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DOI: https://doi.org/10.1007/s42464-024-00251-9