REVIEW ON QUANTITY OF HEXANEDIOL DIACRYLATE (HDDA) USED AS SENSITIZER IN PRODUCTION OF RADIATION PREVULCANIZED NATURAL RUBBER LATEX (RVNRL) Abstrak

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1 REVIEW ON QUANTITY OF HEXANEDIOL DIACRYLATE (HDDA) USED AS SENSITIZER IN PRODUCTION OF RADIATION PREVULCANIZED NATURAL RUBBER LATEX (RVNRL) Sofian Ibrahim 1, Syuhada Ramli 1, Mohd Noorwadi Mat Lazim 1, Khairul Hisyam Mohamed Yusop 1, Najib Mohammad Zakey 1, Hafizuddin Maseri 1, Cosmos George 2, Zarina Mohd Nor 2, Noor Hasni M. Ali 2, & Mohd Sidek Othman 2 1 RAYMINTEX Plant, Malaysian Nuclear Agency, Kajang, Selangor Darul Ehsan, Malaysia 2 MINTec-Sinagama Plant, Malaysian Nuclear Agency, Kajang, Selangor Darul Ehsan, Malaysia Abstrak Salah satu faktor utama yang menyebabkan RVNRL masih lagi tidak dapat dipasarkan secara meluas adalah kekurangan pada sifat mekanikalnya; kekuatan tensile yang rendah (pada sekitar 20 MPa). Dalam ujikaji ini, kuantiti Hexanediol diakrilat (HDDA) yang digunakan dalam penyediaan RVNRL telah dikaji semula kuantitinya supaya dapat mempertingkatkan sifat mekanikal RVNRL. Abstract One of the main factors that caused RVNRL failed to be marketed widely is lack of mechanical properties; low tensile strength (about 20 MPa). In these experiments, the quantity of Hexanediol diacrylate (HDDA) used in the preparation RVNRL was revised in order to improve the mechanical properties RVNRL. Keywords: RVNRL, Hexanediol Diacrylate (HDDA) INTRODUCTION Prevulcanized natural rubber latex prepared by using gamma irradiation (RVNRL) technique has many advantages over the conventionally prepared sulphur prevulcanized natural rubber latex (SPVL) [1]. Besides being nitrosamines free, RVNRL is also friendly to users and environment [2]. RVNRL is available commercially from RAYMINTEX Plant in the Malaysian Nuclear Agency [3]. Being sulphur free RVNRL is currently made useful for commercial production of finger cots and finger stalls of sulphur free grade. Though many other potential products like balloons, examination gloves, surgical gloves, dental dams, condoms could be made from RVNRL, no effort being made to commercialise the products. This is because of the inferior strength of RVNRL products compared to SPVL products; based on ASTM D a (Standard

2 Specification for Rubber Surgical Gloves) minimum tensile strength requirement for producing surgical gloves from natural rubber latex is 24 MPa [4]. Reason that cause disadvantages of RVNRL compared to SVNRL is weakness of carbon-carbon bonding in RVNRL compared with carbon-sulfur bonding in SVNRL. Theoretically, this deficiency can be overcome by increasing the quantity of sensitizer; HDDA used in formulating RVNRL. The objective of this study is to search for optimize quantity of sensitizer; HDDA that can be used to produce RVNRL with higher tensile strength properties. MATERIAL AND METHOD The latex utilised in this work was of a high ammonia type supplied by the TT Latex, Jelebu, Negri Sembilan. The sensitiser used was Hexanediol Diacrylate (HDDA) supplied by Allnex of China. The stabiliser used was potassium laurylic acid and the anti oxidant used was Aquanox LP supplied by Aquaspersion (M) Sdn. Bhd. A typical latex formulation for RVNRL preparation is given in Table 1. The sensitisers, stabiliser and water were first prepared into an emulsion before slowly added into the latex with gentle stirring. Once the addition of the emulsified materials was completed, the latex mixture was left stirring for three hours. It was then transferred into 1 litres capacity screw capped plastic container. Latex then irradiated with gamma rays from a cobalt-60 source at Sinagama Plant for a minimum dose of 12kGy (2.23 kgy/hour). After irradiation, anti oxidant were added into the latex and left stirring for 6 hours. The latex which is now called RVNRL was made into film by coagulant dipping method. RVNRL films, which were leached and dried were cut into dumbbell shape test pieces and their thickness, were recorded. The tensile strength were determined using an Instron 5564 instrument and the procedures of ASTM D412 [5]. The experiment was repeated using different amount of Sensitizer (HDDA); 3.5, 4.5 and 5.5 phr. Table 1: Preparation of Standard RVNRL Formulation (Control) Materials PHR Actual Weight, g NR Latex (62 % TSC) Stabilizer (20%) Antioxidant (45%) HDDA Water Add to 52 % TSC

3 RESULTS & DISCUSSIONS Table 2 below showed mechanical analysis done on the samples. By using 3.5 phr of HDDA as sensitizer and irradiated at minimum 12 kgy at dose rate of 2.23 kgy/hour, RVNRL with higher tensile strength; MPa can be produced. With this result, there is no barrier to produce sulphur, nitrosamines and allergic free rubber latex product; i.e surgical gloves. Table 2: The Influence of the Concentration of HDDA on the Mechanical Properties of RVNRL Concentration of HDDA Mechanical Properties 2.5 phr HDDA (Control) 3.5 phr HDDA 4.5 phr HDDA 5.5 phr HDDA Tensile Strength, MPa %, MPa 700 %, MPa Break % Besides tensile strength, modulus properties of the samples showed increment parallel with the amount of HDAA and it is normally associated with the increased in number of crosslink of polyisoprene molecules. Hence the tensile also should have increased, however no increment in tensile strength was observed in fact there is indication that the HDDA was consumed by radiation polymerization and hydrolysis [6]. The actual concentration of HDDA decreases during irradiation and rate of vulcanization become lower.

4 CONCLUSIONS Our results suggest that 3.5 phr of HDDA is appropriate to produce RVNRL with higher mechanical properties and achieve minimum requirement to produce surgical gloves as stated in ASTM D a (Standard Specification for Rubber Surgical Gloves). ACKNOWLEDGEMENTS Sincere words of thanks to other members of RAYMINTEX and Sinagama Plant for their cooperative effort in making this project a success. REFERENCES 1. Wan Manshol W. Zin, (1992). Radiation Processing of Natural Rubber. A Paper Presented at Kongres dan Seminar Sains dan Teknologi, Kuala Lumpur, Malaysia. 2. Wan Manshol bin W. Zin, Norjanah Mohid and Meor Yahaya Razali, (1995). RVNRL A Potential Material In Latex Dipped Products Manufacturing. Radiat. Phys. Chem.,46,4-6, Wan Manshol W. Zin, (1997). Radiation Vulcanised Natural rubber Latex (RVNRL): Pilot Scale Preparation, Cost and Applications. Full Texts. International Rubber Conference 1997, Kuala Lumpur, Malaysia. 4. ASTM D a Standard Specification for Rubber Surgical Gloves 5. Wan Manshol W. Zin, Norjanah Mohid, Jusoh Hasan, Wan Khairul Amalina Md. Noor and Zulkifli Jaafar, (1993). The Preparation of RVNRL Using Malaysian-Produced Latices. Radiat. Phys. Chem.,42,1-3, K. Makuuchi,Ph.d (2003),An introduction to Irradiation Vulcanization of Natural Rubber Latex,T.R.I Global Co Ltd

5 7. Wan Manshol bin W. Zin, (1998). Semi Industrial Scale RVNRL Preparation, Products Manufacturing and Properties. Radiat. Phys. Chem.,52,1-6, Wan Manshol bin W. Zin, Norjanah bte. Mohid, Jusoh bin Hassan and Ma zam bin Md. Said, (1993). Preparation, Properties and Processability of RVNRL Using Malaysian-Produced Latices. A Paper Presented at the National Executive Management Seminar on Radiation Vulcanisation of Natural Rubber Latex, 22 February 1993, Bangi, Malaysia. 9. Wan Manshol bin W. Zin, (1995). Radiation Vulcanisation Natural Rubber Latex and Its Properties. A Paper Presented at the International Conference on Frontiers of Polymers and Advanced Materials, January 1995, Kuala Lumpur, Malaysia. 10. Wan Manshol bin W. Zin, (1995). Radiation Vulcanisation of Natural Rubber Latex: Applications and Advantages. A Paper Presented at the International Chemical Congress of Pacific Basin Societies, December 1995, Honolulu, Hawaii, USA.

Vulcanisation and Coagulant Dipping of Epoxidised Natural Rubber Latex

Pertanika J. Sci. & Technol. 18 (2): 421 425 (2010) ISSN: 0128-7680 Universiti Putra Malaysia Press Vulcanisation and Coagulant Dipping of Epoxidised Natural Rubber Latex Dazylah Darji * and Ma zam Md