Hydrogenated Liquid Natural Rubber for Compatibility Enhancement of Poly(lactic acid) and Natural Rubber Blends

(Getah Asli Cecair Terhidrogenasi untuk Peningkatan Keserasian Campuran Poli(asid laktik) dan Getah Asli)

MOHAMAD SHAHRUL FIZREE IDRIS¹, NURFARHANA MOHD MUSTAFFARIZAN¹& SITI FAIRUS M. YUSOFF^1,2*

¹Department of Chemical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

²Polymer Research Center (PORCE), Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Received: 12 November 2020/Accepted: 23 February 2021

ABSTRACT

Non-catalytic hydrogenation of liquid natural rubber (LNR) via thermal decomposition of 2,4,6-trimethylbenzenesulfonylhydrazide (MSH) is reported in this study. Parameter studies of the hydrogenation reaction were performed by utilizing the combination of response surface methodology and central composite rotatable design (RSM/CCRD). The effects of each variable and the interaction between two variables (i.e. the MSH:LNR weight ratio and reaction time) were studied. Statistical analysis showed that the reaction time had significantly affected the hydrogenation percentage. A reduced quadratic model equation with the coefficient of determination (R²) value of 0.9875 was developed. The optimized condition as predicted by the software was compared with the experimental data, which deviated in only 0.67, hence indicating that this model was reliable and able to predict the hydrogenation percentage accurately. Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies were used to characterize the microstructure of LNR and hydrogenated liquid natural rubber (HLNR). HLNR was then used as compatibilizer to improve the miscibility of poly(lactic acid)/natural rubber blends. With an addition of 4% HLNR, the tensile strength and impact strength of the blends were slightly improved.

Keywords: Hydrogenation; liquid natural rubber (LNR); surface optimization; 2,4,6-trimethylbenzenesulfonylhydrazide (MSH)

ABSTRAK

Penghidrogenan tanpa mangkin getah asli cair (LNR) melalui penguraian terma 2,4,6-trimetilbenzenasulfonilhidrazida (MSH) dilaporkan dalam kajian ini. Kajian parameter tindak balas penghidrogenan dilakukan dengan menggunakan gabungan kaedah rangsangan permukaan dan reka bentuk komposit putaran tengah (RSM/CCRD). Kesan setiap pemboleh ubah dan interaksi antara dua pemboleh ubah (iaitu nisbah berat MSH: LNR dan masa tindak balas) dikaji. Analisis statistik menunjukkan bahawa masa tindak balas telah mempengaruhi peratusan penghidrogenan secara signifikan. Persamaan model kuadratik dengan nilai pekali penentuan (R²) 0.9875 diperoleh. Keadaan yang dioptimumkan seperti yang diramalkan oleh perisian dibandingkan dengan data uji kaji, yang menyimpang hanya 0.67, sehingga menunjukkan bahawa model ini boleh dipercayai dan dapat meramalkan peratusan penghidrogenan dengan tepat. Spektroskopi inframerah transformasi Fourier (FTIR) dan resonans magnetik nuklear (NMR) digunakan untuk mencirikan struktur mikro LNR dan getah asli cecair terhidrogen (HLNR). HLNR kemudian digunakan sebagai pengserasi untuk meningkatkan keserasian campuran poli(asid laktik)/getah asli. Dengan penambahan HLNR 4%, kekuatan tegangan dan kekuatan hentaman campuran telah meningkat sedikit.

Kata kunci: Getah cecair asli (LNR); penghidrogenan; pengoptimuman permukaan; 2,4,6- trimetilbenzenasulfonilhidrazida (MSH)

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*Corresponding author; email: sitifairus@ukm.edu.my

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