Malaysian Journal of Analytical Sciences Vol 22 No 5 (2018): 885 - 892

LIQUID NATURAL RUBBER TOUGHENED POLY(LACTIC ACID) BLEND: EFFECTS OF COMPATIBILIZER TYPES AND LOADINGS ON THERMO-MECHANICAL PROPERTIES

(Adunan Asid Polilaktik Diperkuat Getah Asli Cecair: Kesan Jenis dan Kandungan Penserasi Terhadap Sifat Terma-Mekanik)

Mohd Farid Hakim Mohd Ruf, Sahrim Ahmad, Ruey Shan Chen*, Dalila Shahdan, Farrah Diyana Zailan

School of Applied Physics,

Faculty of Science and Technology,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

*Corresponding author: chen@ukm.edu.my

Received: 20 July 2017; Accepted: 28 April 2018

Abstract

This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid (PLA-g-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the mechanical and thermal properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA were the first self-synthesized by mixing maleic anhydride (MA) and dicumyl peroxide (DCP) which acted as initiator with the PLA and natural rubber (NR), respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via melt-blending method. The loading of PLA-g-MA and NR-g-MA was varied between 5, 10 and 15%, respectively. By comparing to the control sample (neat PLA/LNR blend), the addition of PLA-g-MA with 5 and 10% led to increment in tensile strength up to 22 MPa, whereas NR-g-MA promoted a negative trend of tensile properties to the blends. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) results showed the enhanced thermal stability for PLA/LNR/PLA-g-MA blend. Fourier transform infrared (FTIR) analysis confirmed the chemical interaction between the PLA and NR components where the grafted copolymers were successfully grafted onto PLA backbone and bonded with NR.

Keywords: polymer blend, polylactic acid, toughening agent, compatibilizer, thermal

Abstrak

Kajian ini dijalankan bagi mengkaji kesan penambahan kopolimer maleik anhidrida cantuman-asid polilaktik (PLA-g-MA) dan maleik anhidrida cantuman-getah asli (NR-g-MA) terhadap sifat mekanik and terma polimer adunan asid polilaktik/cecair getah asli (PLA/CGA). Sebelum penyediaan adunan, PLA-g-MA dan NR-g-MA terlebih dahulu disintesiskan dengan mengadun maleik anhidrida (MA) dan dikumil peroksida (DCP) yang bertindak sebagai pemula bersama dengan PLA dan getah asli (GA). Adunan PLA/LNR, PLA/LNR/PLA-g-MA dan PLA/LNR/NR-g-MA disediakan dengan menggunakan kaedah pengadunan dalaman. Kandungan PLA-g-MA dan NR-g-MA masing-masing divariasikan kepada 5, 10 dan 15%. Berbanding dengan sampel kawalan (adunan PLA/LNR), penambahan PLA-g-MA sebanyak 5 dan 10% memberikan peningkatan terhadap kekuatan tegangan sehingga 22 MPa manakala NR-g-MA memberikan corak penurunan terhadap adunan. Keputusan kalorimeter pemgimbasan pembezaan (DSC) dan analisa termogravimetri (TGA) menunjukkan peningkatan kestabilan terma adunan PLA/LNR/PLA-g-MA. Analisa spektroskopi inframerah transformasi Fourier (FTIR) membuktikan interaksi kimia berlaku antara komponen PLA dan NR di mana kopolimer cantuman berjaya dicantum pada tulang belakang PLA dan diikat dengan NR.

Kata kunci: polimer adunan, asid polilaktik, agen penguat, penserasi, terma

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