Hydrolysis of cotton fabric waste to produce microcrystalline cellulose (MCC) was carried out using 2.5 N hydrochloric acid at 100 degrees C for 30 min. Characterization of the structure, morphology, particle size as well as the thermal decomposition of the obtained MCC were studied using X-ray diffractometer, scanning electron microscope and laser light scattering particle size analyzer and thermogravimetric analyzer, respectively. These results indicated that the obtained MCC had a fibrous structure of a 40 microm average particle size and possessed a form of highly native crystalline cellulose I. In addition, its maximum degradation temperature was observed at 350 degrees C. The poly(vinyl chloride) (PVC) films in this work were produced by first blending the produced MCC with PVC resin in amounts of 5-30 parts per hundred of resin. The blends were then made into film using a two-roll mill. The tensile properties of the film were measured using a Universal Testing Machine. The biodegradation tests were carried out in soil and in a moisture-controlled chamber. The biodegradability was estimated by the loss of mass, moisture absorption capacity and electron microscope studies. It was found that the tensile strength and Young's modulus of the blends increased with increasing amounts of MCC. Similarly, moisture absorption and biodegradability of the films were also increased as the amount of MCC increased. The results implied that MCC behaved not only as a reinforcing filler but also as a biodegradability promoter of PVC films.
Microcrystalline cellulose (MCC) was prepared by hydrolyzing waste cotton fabric with 2.5 N hydrochloric acid at 100°C for 30 min. The structure, morphology, particle size, and thermal property of the prepared MCC were characterized by X-ray diffraction, scanning electron microscope, laser light scattering particle size analyzer, and thermogravimetric analyzer, respectively. The X-ray diffraction pattern showed that the obtained MCC has typical crystal lattice of cellulose I. The fibrous-shaped particle of MCC possessed an average particle size of approximately 40 μm and thermal degradation temperature of 350°C. The produced MCC was blended with concentrated natural rubber (NR) latex at the amounts of 10, 20, and 30 parts per hundred of dry rubber. The blended latex was cast into a sheet on a glass mold, allowed to air dry, and subsequently cured at 100°C for 3 h. After curing, samples were tested for their tensile properties, water absorption, morphology, and biodegradability. It was found that the tensile properties of NR decreased when incorporated with MCC. However, the 100 NR/20 MCC sample showed the highest tensile strength and percent elongation at break. Water absorption and biodegradability of the sample were enhanced as the amount of MCC was increased. The results indicated that MCC caused important effects in promoting the biodegradability of NR.
In this study, grafting of hyperbranched polyamidoamine (PAMAM) polymer onto ultrafine silica followed by functionalization via the introduction of phosphonic acid groups into the branch ends was performed. First, an initiating site was incorporated into the silica surface by reacting the silica silanol group with 3-aminopropyltriethoxysilane, producing amino-functionalized silica. The free amine group content was altered by varying the ratio of methanol to water in the hydrolysis step of the silanization reaction. Grafting of PAMAM was attained by three rounds of sequential Michael addition of silica amino groups to methyl acrylate and amidation of the resulting terminal methyl ester groups with ethylenediamine. Completion of the grafting reaction in each step was clearly confirmed using FTIR analysis. Excessive ethylenediamine and unattached hyperbranched PAMAM present in the reaction product were removed by dialysis with a molecular weight cutoff of 6000-7000 Daltons. However, the amino group content determined in each step was found to be significantly lower than theoretically expected, perhaps indicative of side reactions and, in later stages, steric hindrance. The resultant hyperbranched PAMAM-grafted onto silica was functionalized by phosphorylation of the terminal amino groups by a Mannich type reaction, producing the phosphorylated hyperbranched PAMAM-grafted silica. Then its application on cotton fabric to produce fireretardant cellulose was tentatively investigated.
Polyethylene glycolated bisphenol A (PEGBPA), a hydrophilic-hydrophobic compound, was synthesized and applied onto polyester fabric using a pad-dry-cure method to impart a durable hydrophilic property. After coating and heat fixation, the treated fabrics were evaluated for wettability by measurement of the net moisture regain and wicking distance, and their surfaces were characterized by SEM and ATR/FTIR spectroscopy. The durability of the treated fabrics were tested by ten standard repeat washings and samples were characterized for their wettability after each wash. The surface properties of the fabric changed from hydrophobic to hydrophilic after heat treatment with the coating agent PEGBPA. Using the degree of increased moisture regain and wicking distance of the treated fabrics as a guide, optimal treatment was attained by coating with 10-20 g/ L PEGBPA followed by 160-180 C heat treatment for 3 min. Wash fastness evaluations, coupled with SEM and ATR/FTIR analyses, showed that PEGBPA exhibited good adhesion onto the PET surface and was capable of withstanding repeated washings. It was concluded that the coating adhesion solely depended on physical aspects, such as hydrophobic-hydrophobic interactions between the bisphenol A segment of PEGBPA and the PET aromatic segment.
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