Malaysian Journal of Analytical Sciences Vol 19 No 4 (2015): 874 - 880

 

 

 

EFFECT OF AMPHIPHILIC ALKYL CHAIN LENGTH UPON PURIFIED LATEX STABILITY

 

(Kesan Pemanjangan Rantai Alkil Ampifilik ke atas Kestabilan Lateks Tulen)

 

Amira Amir Hassan* and Amir Hashim Mohd Yatim

 

Rubber Research Institute of Malaysia,

Malaysia Rubber Board, 47000 Sg. Buloh, Selangor Malaysia

 

*Corresponding author: amira@lgm.gov.my

 

 

Received: 23 November 2014; Accepted: 27 June 2015

 

 

Rubber particles in purified latex (PL) are stabilized by a film of protein and fatty acid soap (surfactant). Saturated straight-chain fatty acid soaps can assist an enhancement of latex stability. However, whether the alkyl chain length plays an important role in increasing the stability is still an issue. The aim of this study is to investigate the effect of alkyl chain length of anionic surfactant on the stability of purified latex. The fatty acid soap of decanoate (9), laurate (11), sodium dodecyl sulphate (SDS) (12) and palmitate (15) were used. The numbers in parentheses indicating the number of carbon present in alkyl chain of the soap. The results showed that the impact of alkyl chain length on the stability of latex is in the order of laurate > decanoate > SDS > palmitate > purified latex accordingly. The alkyl chain length does giving a significant effect on latex stability after longer stirring time. The particle size of latex with the presence of surfactant is greater compare to a single particle itself due to extension of particles diameter. Thus suitable interaction of the nonpolar tail of  surfactant with the hydrophobic regions of  latex surface played a major role in maintaining a stable latex system.

 

Keywords: anionic surfactant, conductometric titration, stability

 

Abstrak

Zarah-zarah lateks tulen distabilkan oleh protein dan asid lemak tepu (surfaktan). Panjang asid lemak tepu dapat meningkatkan kestabilan lateks tulen. Walaubagaimanapun, kesan terhadap panjang rantaian asid lemak tepu dalam kestabilan lateks tulen masih menjadi isu. Tujuan kajian ini adalah untuk menyiasat kesan panjang rantaian surfaktan anionik keatas lateks tulen. Asid lemak tepu iaitu dekanoat (9), laurat (11), natrium dodecil sulfat (SDS) (12) dan palmitat (15) telah digunakan. Nombor mewakili bilangan karbon pada rantaian alkil surfaktan. Hasil kajian menunjukkan pemanjangan rantai alkil memberi kesan terhadap kestabilan lateks tulen mengikut susunan laurat > dekanoat > SDS > palmitat > lateks tulen. Panjang rantai alkil dalam sistem lateks memberi kesan keatas kestabilan lateks selepas masa pengacauan  yang lama. Saiz zarah juga menunjukkan peningkatan dengan kehadiran surfaktan di dalam sistem. Oleh itu, interaksi yang sesuai oleh ekor surfaktan tidak berkutub dengan permukaan hidrofobik lateks boleh berlaku dan seterusnya memelihara kestabilan sistem lateks.

 

Kata kunci: surfaktan anionik, pentitratan, kestabilan

 

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