Kesan penambahan pengisi sekam padi dan tanah liat ke dalam matriks getah asli getah asli cecair polietilena berketumpatan tinggi (NR/LNR/HDPE), NR/HDPE dan HDPE terhadap sifat mekanik dan morfologi adunan telah dikaji. Pemprosesan adunan dilakukan pada suhu 140°C dan kadar percampuran 50 r.p.m. selama 16 minit. Pra-pemanasan pengisi selama 4 minit pada suhu 80°C dilakukan sebelum pengadunan dengan matriks bagi meminimumkan kesan lembapan. Getah asli cecair digunakan sebagai agen pengserasi dalam adunan komposit. Pengisian sekam padi (SP) dan tanah liat (TL) dalam matrik HDPE, NR/HDPE serta NR/LNR/HDPE umumnya menurunkan nilai kekuatan tensil dan kekuatan hentaman tetapi meningkatkan nilai modulus. Kehomogenan adunan komposit berpengisi yang dikenal pasti melalui pemeriksaan morfologi menggunakan mikroskop imbasan elektron (SEM) menunjukkan masalah aglomerasi dan interaksi antara muka dalam komposit berlaku. Kelikatan leburan dan interaksi antara bahan menentukan arah pergerakan serta serakan pengisi dalam komposit. Daripada keputusan yang diperolehi dan merujuk kedua-dua sifat pengisi, SP adalah lebih serasi dengan NR disebabkan potensi interaksi antara kumpulan berfungsi permukaan pengisi selulosa (SP) seperti –OH dengan ikatan ganda dua NR berbanding TL. Ciri fizik permukaan TL yang kurang bersifat hidrofilik berbanding SP pula menyebabkan TL lebih cenderung berinteraksi dan tersebar dengan baik dalam HDPE.
Ultra-high temperature is a process that involves heating of milk to a very high temperature to produce sterile milk products.
However, food poisoning due to consumption of UHT milk still happen in Malaysia. This study was done to develop a
film that is made by poly(L-lactic acid) (PLLA) to detect the presence of microorganisms in UHT milk products. UHT milk
that was used in this study was full cream milk. Contaminated milk that contained Bacillus cereus was made to conduct
a model system on the relationship between colony forming unit of microorganisms and contact angle. Contaminated
milk was also used as a control sample to study the difference of milk properties between fresh and contaminated milk.
Physicochemical analysis (Brix, colour, pH and contact angle) and microbiological analysis (total plate count) were
done to UHT milk sample as soon as the packaging of the milk was unsealed. Analysis was done with 30 min time interval
until 4 h and 30 min since the unsealing of packaging. The results showed that presence of microorganisms in UHT milk
was detected after the milk product was unsealed and exposed to environment for 3 h and 30 min. Contact angle resulted
from the presence of microorganisms in UHT milk was 64.34 - 65.44° with its colony forming unit, 2.1 – 3.9 cfu/mL.
Therefore, the potential usage of contact angle on PLLA thin film with respect to colony forming unit (cfu) in detecting
the presence of microorganisms in UHT milk product was attained and well modelled.