Abstract
Differential Scanning Calorimetry (DSC) is employed to study the changes in enthalpy of natural rubber latex samples when heated under a controlled temperature program. It is found that the mass normalized areas of the DSC curves between room temperature and 170 °C for different latex samples are inversely proportional to the dry rubber content (DRC) of the samples, measured following the weighing and drying method. The changes in total enthalpy of the samples in this temperature range are interpreted as due to the variations in the quantity of water present in the samples. The measurements have been repeated by diluting selected samples with known quantities of water, and it is found that the normalized areas of the DSC curves are directly proportional to the amount of water added to the latex. The method can be used to estimate the DRC of natural rubber latex accurately. Its advantages and limitations are discussed.
Similar content being viewed by others
References
Nair NU, Thomas M, Sreelatha S, Simon SP, Vijaya Kumar KR, George PJ. Clonal Variation in lipid composition in the latex of Hevea brasiliensis and its implications in latex production. Indian J Nat Rubber Res. 1993;61–62:143–5.
Sarath Kumara PH. Latex collection. In: Tillerkeratne LMK, Nugawela A, Seneviratne WMG, editors. Handbook of rubber: processing. Sri Lanka: Rubber Research Institute of Sri Lanka; 2003.
Kuriakose B. Primary processing. In: Sethuraj MR, Mathew NM, editors. Natural rubber: biology, cultivation and technology. Amsterdam: Elsevier Science Publishers; 1992.
Cheaw CH. Metrication and changes to the ‘Chee’ method of determining the dry rubber content of field latex. Plant Bull Rubber Res Inst Malaysia. 1981;169:136–49.
Gambhir PN, Joshi DK, Tiwari PN, Mani J. Rapid determination of dry rubber content of natural rubber latex by low-resolution pulsed NMR technique. J Nat Rubber Res. 1993;8(3):208–12.
Rejikumar R, Najmal Hussain S, Philip J. Measurement of dry rubber content of natural rubber latex with a capacitive transducer. J Rubber Res Inst Malaysia. 2007;10(1):17–25.
Khalid KB, Hassan YM, Ramali AR. Measurement of dry rubber content and total solid content of Hevea latex by microwave techniques. In: Proceedings of the RRIM growers conference, Malacca; 1989. p. 493–504.
Williard HH, Merrit LL Jr, Dean JA. Instrumental methods of analysis. 3rd ed. New York: Van Nostrand Company Inc; 1985.
Wunderlich B, Pyda M. Application of the advanced thermal analysis system (ATHAS) to differential scanning calorimetry (DSC) and temperature-modulated DSC of polymers. J Reinf Plast Compos. 1999;18(6):487.
Bajsic EG, Rek V, Sendijarevic A, Sendijarevic V, Frisch KC. DSC study of morphological changes in segmented polyurethane elastomers. J Elastomers Plast. 2000;32:162–82.
Khandpur RS. Handbook of analytical instruments. Professional electrical engineering series. Tata McGraw Hill; 2006.
Runquist O, Creswell C J, Thomas J. Thermodynamics and kinetics: in chemical principles. Minneapolis: Burgas Publishing Company; 1979.
Acknowledgements
The authors thank the Sophisticated Analytical Instruments Facility (SAIF), STIC, Cochin 682 022 for help with DSC measurements. We also thank Dr. James Jacob, Director, Rubber Research Institute of India, Kottayam for his interest in this study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rejikumar, R., Philip, J. Estimation of dry rubber content in natural rubber latex by differential scanning calorimetry. J Therm Anal Calorim 101, 1047–1050 (2010). https://doi.org/10.1007/s10973-010-0716-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10973-010-0716-x