The effect of aging on mechanical properties of natural rubber latex (NRL) products filled with alkanolamide-modified cassava peel waste powder (CPWP) was studied. CPWP used as fillers was prepared by milling and sieving it until the size of 100 mesh. The powder then was dispersed in a suspension containing water and alkanolamide in order to modify the prepared powders. The dispersion system of 10 pphr (part per hundred rubber) then was added into NRL matrix followed by pre-vulcanization at 70°C for 10 minutes. The NRL compound then were casted into films by coagulant dipping method then dried at 120°C for 10 minutes. Afterwards, the films were allowed to cool at room temperature for 24 hours before being aged in a circulation of hot air for 24 hours at 70°C. The properties such as tensile strength, tensile modulus, and elongation at break were evaluated between the aged samples and the unaged samples. From this study, it showed that the aged films have increasing value of tensile strength and tensile modulus while the value of elongation at break decreases. These datas are supported by Scanning Electron Microscope (SEM) micrographs which indicate that the change of morphology in NRL films occurs before and after aging.

The purpose of this research was to study the effect of drying time on the mechanical properties of natural rubber latex filled with cassava peel waste modified alkanolamide. Cassava peel is a waste, containing cellulose which is potential as fillers in natural rubber ABSTRAKPenelitian ini bertujuan untuk mempelajari pengaruh waktu vulkanisasi terhadap sifat mekanik produk lateks karet alam berpengisi kulit singkong termodifikasi alkanolamida. Kulit singkong merupakan limbah yang mengandung selulosa dan berpotensi untuk digunakan sebagai bahan pengisi dalam produk lateks karet alam. Kulit singkong dikeringkan dan dihaluskan hingga berukuran 100 mesh. Alkanolamida merupakan surfaktan nonionik yang disintesis dari bahan baku RBDPS (Refined Bleached Deodorized Palm Stearin) dan dietanolamina. Alkanolamida mengandung gugus polar yang dapat memodifikasi tepung kulit singkong dan membentuk ikatan kimia yang kuat dengan lateks karet alam. Proses pembuatan produk lateks karet alam dimulai dengan proses pravulkanisasi pada suhu 70°C hingga lateks karet alam telah matang dan bilangan kloroform telah mencapai angka 3. Lateks karet alam dicetak dengan menggunakan teknik pencelupan berkoagulan dengan metode pengeringan pada suhu 120°C selama 10 menit dan 20 menit. Hasil penelitian menunjukkan waktu vulkanisasi yang lebih lama dapat meningkatkan nilai densitas sambung silang dan kekuatan tarik produk lateks karet alam hingga penambahan 15 phr tepung kulit singkong.Kata kunci: waktu vulkanisasi, alkanolamida, kulit singkong, lateks karet alam. PENDAHULUANLateks karet alam merupakan hasil penyadapan pohon Hevea brasiliensis. Lateks karet alam segar mengandung 30-40% partikel hidrokarbon karet yang terdiri dari cis 1,4 poliisoprena dan 2-3% protein (Jayanthy & Sankaranarayanan,

Cassava peel is one of agricultural waste that abundantly found in environment. One approach to manage this waste is to apply it as filler in natural rubber latex. In this work, the cassava peel waste (CPW) was powdered and dispersed in alkanolamide-water dispersion system to modify its surface. The amount of fillers used was 0, 5, 10, 15, 20 and 25 phr (part per hundred rubber) and loaded in natural rubber latex (NRL) formulation system. The products then were formed by dipping method after the NRL formulation was pre-vulcanized at 70°C. The observed parameter includes crosslink density, tensile strength, tensile modulus and elongation at break. Scanning Electron Microscope (SEM) was used to study the morphology of tensile fracture in NRL film. The results show that 10 phr loading of modified fillers increases the crosslink density, tensile strength, and tensile modulus but decreases the elongation at break. SEM study also reveals that higher filler loading above 10 phr will create the agglomeration in rubber matrix.