Abu, Norhidayah
(2016)
Preparation, Characterization And Slow-Release Properties Of Biocomposites Comprising Chitosan Encapsulated In Natural Rubber Matrices.
Masters thesis, Universiti Sains Malaysia.
Abstract
Projek penyelidikan ini terdiri daripada dua bahagian. Pada bahagian pertama, kesan pH ke atas kestabilan gel chitosan berasid (CTSAc) bersama 1-Naftol (produk dilabelkan sebagai CTSAc/1-N) atau 2-Naftol (produk dilabelkan sebagai CTSAc/2-N) ditentukan. Dalam air berasid (pH ≤ 4), CTSAc/1-N atau CTSAc/2-N membentuk gel dan pecah dengan mudah. Dalam air neutral (pH ≈ 7), CTSAc/1-N dan CTSAc/2-N membentuk gel tetapi masih kelihatan utuh walaupun selepas dua minggu. Dalam air beralkali (pH ≥ 9), CTSAc/1-N dan CTSAc/2-N sukar membentuk gel walaupun selepas direndam selama tiga bulan. Selain itu, biokomposit tanpa naftol yang terdiri daripada CTSAc terkandung dalam getah asli tak tersilang ({CTSAc}NRucl) dan getah asli tersilang ({CTSAcl}NRc) disediakan. Kajian pengambilan air oleh NRucl, NRcl, {CTSAc}NRucl dan {CTSAc}NRcl telah dikaji. Daripada kajian ini, jumlah peratusan air dalam NRcl, NRucl, {CTSAc}NRcl dan {CTSAc}NRucl selepas 48 jam didapati berjumlah 1.8%, 3.0%, 75% dan 131%, masing-masing. Pada bahagian kedua, biokomposit terdiri daripada CTSAc/1-N atau CTSAc/2-N dan terkandung dalam NRucl ({CTSAc/1-N}NRcl) atau dalam NRcl ({CTSAc/2-N}NRucl) disediakan. Semua bahan polimer dicirikan menggunakan kaedah spektroskopi FT-IR, TGA dan VPSEM.
This research project consists of two parts. In the first part, we determined the stability of acidified chitosan (CTSAc) gel incorporated with known amounts of either 1-Naphthol (product designated as CTSAc/1-N) or 2-Naphthol (product designated as CTSAc/2-N) in water with different pH values. In acidified water (pH ≤ 4), CTSAc/1-N or CTSAc/2-N swelled tremendously and broke apart easily. In neutral water (pH ≈ 7), CTSAc/1-N and CTSAc/2-N swelled but remained intact even after two weeks. In alkalized water (pH ≥ 9), CTSAc/1-N and CTSAc/2-N hardly swelled even after being soaked for three months. In addition, biocomposites comprised of solely CTSAc encapsulated in uncrosslinked natural rubber ({CTSAc}NRucl) and crosslinked natural rubber ({CTSAc}NRcl) were prepared. From the water uptake study, the percentage amount of water in NRcl, NRucl, {CTSAc}NRcl and {CTSAc}NRucl after 48 h was found to be 1.8%, 3.0%, 75% and 131%, respectively. In the second part, biocomposites comprised of CTSAc/1-N or CTSAc/2-N encapsulated in NRucl ({CTSAc/1-N}NRucl or {CTSAc/2-N}NRucl) and in NRcl ({CTSAc/1-N}NRcl or {CTSAc/2-N}NRcl) were prepared. All polymeric materials were characterized by means of FT-IR spectroscopy, TGA and VPSEM.
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