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https://ptsldigital.ukm.my/jspui/handle/123456789/499812| Title: | The effect of pretreatment on molecular weight of kenaf core pulp for regenerated cellulose productions |
| Authors: | Farah Nadia Mohammad Padzil (P68043) |
| Supervisor: | Sarani Zakaria, Prof. Dr. |
| Keywords: | Kenaf core pulp Cellulose productions Acid hydrolysis Electron beam irradiation Molecular weight Dissertations, Academic -- Malaysia |
| Issue Date: | 28-Jun-2016 |
| Description: | The research was conducted to investigate the effect of acid hydrolysis (AH) and electron beam irradiation (EBI) pretreatments on molecular weight (Mŋ) of kenaf core cellulose pulp that would be used to produce regenerated cellulose membrane/hydrogel using aqueous alkaline/urea system. After a series of bleaching steps, the bleached kenaf core cellulose pulp (BK) was hydrolyzed in 0.5M H2SO4 at room temperature (RT) for different times ranging from 10 min to 90 min. The Mŋ of hydrolyzed kenaf cellulose pulp (HK) has been reduced from 14.5×104 to 2.55×104 as the hydrolyzed time increased. Then, HK samples were dissolved in aqueous NaOH/urea and LiOH/urea system to form a regenerated cellulose membrane. The cellulose solubility increased as the cellulose Mŋ decreased. The cellulose dissolution in aqueous LiOH/urea showed better solubility compared to NaOH/urea system. XRD test showed the crystallinity index (CrI) of the HK increased as the hydrolysis time increased but decreased after regenerated membrane was formed. This is due to the destruction of amorphous area during hydrolysis treatment and the disruption of crystalline area during dissolution process, respectively. FESEM result showed membrane that produced using LiOH/urea had smaller pore size compared using NaOH/urea system. For the second pretreatment, BK was irradiated with electron beam at irradiation dosage 10 to 70 kGy. Then, the irradiated kenaf cellulose pulp (IK) samples were dissolved using similar aqueous alkaline/urea system for hydrogel production. The Mŋ of IK reduced from 14.5×104 to 2.25×104 as the irradiation dosage increased. The solubility increased up to 97.93% and 99.41% for IK-70 kGy that dissolved in NaOH/urea and LiOH/urea solution, respectively. Eventhough the solubility was high but the viscosity of cellulose solution produced at high irradiation dosage was too low which were 58 cP and 96 cP for NaOH/urea and LiOH/urea system, respectively. This caused the regenerated hydrogel unable to form. A lot of β-1,4 glycosidic bond were broken which has been proven by increment of β-cellulose content when irradiation dosage increased that leads to decreased in cellulose fibre zero-span tensile index besides increased the cellulose solubility and decreased cellulose solution viscosity. The FESEM image exhibited bigger pore size for hydrogel produced using irradiated-cellulose (IKH) compared to hydrogel produced using untreated-cellulose (BKH). Besides that, IKH had high transparency and degree of swelling. This study has proven that both AH and EBI pretreatments has reduced the cellulose Mŋ, thus, enhanced the properties of regenerated cellulose products formed with assisted by aqueous alkaline/urea system.,Certification of Master's/Doctoral Thesis" is not available |
| Pages: | 113 |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi |
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