Preparation and Characterization of Wood Polymer Nanocomposites (WPNCs) for Sustainable Application

Md Tipu, Sultan (2019) Preparation and Characterization of Wood Polymer Nanocomposites (WPNCs) for Sustainable Application. PhD thesis, Universiti Malaysia Sarawak (UNIMAS).

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Abstract

ABSTRACT Wood impregnation is one of the oldest and the most frequently used techniques to improve the wood properties. This treatment offers a wide range of protection depending on used impregnates. Impregnation can make the wood more resistant to decay, less flammable, and can improve the mechanical property. Generally, the aim of this thesis is to improve the wood properties to already known technologies. To improve the wood properties, it is needed to simultaneously pluck out the lumen (by hydrophobic material) and the –OH group of raw wood, but the hydrophobic organic polymer cannot make a strong bond with wood. In this study, both the –OH groups, and lumens of wood were plucked out simultaneously by 4-methyl catachol or by a mixture of polymer/coupling agent/hydrophopbic nanoclay. In this study, 3-(trimethoxysilyl)propyl methacrylate (MSPMA), glycidyl methacrylate (GMA), maleic acid (MA), and ethylene glycol dimethacrylate (EGDMA) worked as a coupling agent between wood and polystyrene. One functional group of these coupling agents substituted the –OH group of wood and the other functional group having double bond formed a covalent bond with styrene by in situ polymerization. The effect of nanoclay on physical mechanical, thermal and biodegradation resistance properties of ST/coupling agent impregnated wood was studied. Two types of fungus, white-rot (Tramedes versicolor) and brown-rot (Coniophora putena), were used to study the biodegradability of impregnated wood. FT-IR result also proved that nanoclay helped to increase the interaction between wood and ST. The XRD result proved that nanoclay was exfoliated into wood. The SEM results showed that ST/coupling agent/nanoclay impregnated wood had smooth surfaces compared to ST/coupling agent impregnated wood and raw wood due to the exfoliation of clay into wood cell wall and polymer. With some exceptions, the MOR value, water uptake resistance and decay resistance of ST/coupling agent/clay impregnated wood were higher than that of ST/coupling agent impregnated wood. This is because hydrophobic nanoclay particles have high surface area, which increased the hydrophobicity in wood and also increased the compatibility between wood molecule and ST/coupling agent. The crystalinity breaking enthalpy of ST/coupling agent impregnated wood was higher than that of the ST/coupling agent impregnated/clay impregnated wood. So it can be expected that nanoclay increased the compatability between wood components and polystyrene. TGA results showed that the thermal stability (between 150-350 °C) of ST/coupling agent/clay impregnated wood were higher than that of ST/coupling agent impregnated wood. This higher stability of ST/coupling agent/clay impregnated wood can be explained that the wood and polymer were encapsulated by nanoclay. Finally it can be said that polymer/coupling agent/clay impregnated wood showed better wood properties than only polymer/coupling agent impregnated wood. Keywords: Wood, coupling agent, polymer, nanoclay Penyediaan dan Pencirian Nanokomposit Polimer Kayu (WPNCs) untuk Aplikasi Mapan ABSTRAK Impregnasi kayu adalah salah satu teknik yang paling lama dan paling sering digunakan untuk memperbaiki sifat kayu. Rawatan ini menawarkan pelbagai jenis perlindungan bergantung kepada penggunaan yang digunakan. Impregnasi boleh membuat kayu lebih tahan terhadap kerosakan, kurang mudah terbakar, dan dapat meningkatkan sifat mekanik. Secara umum, tujuan tesis ini adalah untuk meningkatkan sifat kayu kepada teknologi yang sudah diketahui. Untuk memperbaiki sifat-sifat kayu, ia perlu untuk secara serentak mengeluarkan lumen (bahan hidrofobik) dan kumpulan kayu mentah -OH, tetapi polimer organik hidrofobik tidak dapat membuat ikatan yang kuat dengan kayu. Dalam kajian ini, kedua kumpulan -OH, dan lumen kayu dikeluarkan secara serentak oleh 4-metil catachol atau dengan campuran polimer/gandingan ejen/hidrofobic nano zarah tanah liat. Dalam kajian ini, 3-(trimethoxysilyl)propyl methacrylate (MSPMA), glycidyl methacrylate (GMA), asid maleik (MA), dan etilena glikol dimethacrylate (EGDMA) berfungsi sebagai agen gandingan antara kayu dan polistirena. Satu kumpulan fungsian ejen gandingan ini menggantikan kumpulan kayu -OH dan kumpulan fungsi lain yang mempunyai ikatan berganda membentuk ikatan kovalen dengan stirena dengan pempolimeran in situ. Kesan nano zarah tanah liat pada sifat-sifat rintangan mekanikal, terma dan biodegradasi fizikal ST/gandingan ejen yang diresapi kayu telah dikaji. Dua jenis cendawan, Putih-bulat (Tramedes versicolor) dan Coklat-rot (Coniophora putena), digunakan untuk mengkaji biodegradibiliti kayu impregnasi. Keputusan FT-IR juga membuktikan bahawa nano zarah tanah liat membantu meningkatkan interaksi antara kayu dan ST. Hasil XRD membuktikan bahawa nano zarah tanah liat terkelupas menjadi kayu. Keputusan SEM menunjukkan bahawa bahan ST/gandingan ejen/nano zarah tanah liat yang diperbuat daripada kayu mempunyai permukaan halus berbanding dengan bahan ST/gandingan agen yang telah diresapi kayu dan kayu mentah kerana pengelupasan tanah liat ke dinding sel kayu dan polimer. Dengan beberapa pengecualian, nilai MOR, rintangan penyerapan air dan rintangan kerosakan ST/gandingan agen/kayu yang dilaras liat adalah lebih tinggi daripada kayu ST/gandingan agen yang diresapi. Ini adalah kerana zarah nano zarah tanah liat hidrofobik mempunyai luas permukaan yang tinggi, yang meningkatkan hidrofobisiti di dalam kayu dan juga meningkatkan keserasian antara molekul kayu dan agen ST/gandingan. Entalpi pecah kristaliniti daripada ST/gandingan ejen yang diresapi kayu adalah lebih tinggi daripada yang ST/gandingan ejen yang diresapi/tanah liat diresapi. Oleh itu, diharapkan nano zarah tanah liat meningkatkan keserasian antara komponen kayu dan polistirena. Keputusan TGA menunjukkan bahawa kestabilan terma (antara 150-350 °C) daripada ST/gandingan ejen/tanah liat yang diresapi lebih tinggi daripada kayu ST/gandingan ejen yang telah diresapi. Ini kestabilan tinggi ST/gandingan ejen/kayu yang dilaraskan tanah liat boleh dijelaskan bahawa kayu dan polimer telah dirumuskan oleh nano zarah tanah liat. Akhirnya ia boleh dikatakan bahawa agen polimer/gandingan/kayu yang dilaras tanah liat menunjukkan sifat kayu yang lebih baik daripada hanya agen polimer/gandingan yang diresapi kayu. Kata kunci: Kayu, agen gandingan, polimer, nano zarah tanah liat

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