Sains Malaysiana 31: 57-63 (2002)                                                                                                Sains Fizis dan Gunaan /

Physical and Applied Sciences

Modifikasi Kimia ke atas Getah Asli Cecair

dengan Kaedah Penghidroklorinan

(Chemical Modification of Liquid Natural Rubber

Via Hydrochlorination)

Rusli Daik, Mohd Norhisham Satiar & Ibrahim Abdullah

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi,Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E., Malaysia

ABSTRAK

Modifikasi kimia ke atas getah asli cecair telah dijalankan melalui tindak balas penghidroklorinan dalam pelarut benzena dengan melalukan gas hidrogen klorida yang dihasilkan daripada tindak balas antara asid sulfurik pekat dan ammonium klorida. Hasil tindak balas merupakan pepejal lembut berwarna perang pekat. Kehadiran klorin dalam sampel telah ditentukan menggunakan analisis unsur dan spektroskopi FTIR. Puncak pada 736 cm^-1 dalam spektrum FTIR bagi sampel getah asli cecair terhidroklorin menunjukkan wujudnya ikatan C-CI. Analisis termogravimetri menunjukkan getah asli cecair terhidroklorin kurang stabil terhadap haba berbanding dengan getah asli cecair yang asal. Berdasarkan analisis unsur, penentuan nombor iodin, spektroskopi FTIR dan analisis termogravimetri, sampel dengan darjah penghidroklorinan sebesar 35 dan 62 % telah berjaya dihasilkan.

ABSTRACT

Chemical modification of liquid matural rubber was carried out via hydrochlorination reaction. Hydrogen chloride that was produced from the reaction between ammonium chloride and concentrated sulphuric acid was bubbled into liquid natural rubber solution in benzene. The product was a soft solid in dark brown colour. The presence of chlorine in the samples produced was detected using elemental analysis and FTIR spectroscopy. The peak at 736 cm^-1 in the FTIR spectrum of the hydroclorinated samples indicated the presence of C-C1 vibration. Thermogravimetry analysis showed that the hyrdrochlorinated product was less stable against heat as compared to the orginal samples. Samples of hydrochlorinated liquid natural rubber with degree of hydrochlorination of 35 and 62% were successfully prepared as calculated based on results obtained from elemental analysis, determina­tion of iodine number, FTIR spectroscopy and thermogravimetric analysis.

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