Chitosan-Tripoly Phosphate (CS-TPP) Synthesis Through Cross-linking Process: the Effect of Concentration Towards Membrane Mechanical Characteristic and Urea Permeation
Crosslinking reactions are required to modify the functional groups on chitosan and to increase the number of active groups of chitosan. In this study crosslinking reaction of tripolyphospate (TPP) groups on chitosan was conducted in order to produce membrane which functions as candidate of hemodialysis membrane. The mole ratio between chitosan and NaTPP was varied to obtain the best composition of modified materials. Study of TPP concentration effect towards membrane characteristics was conducte durea permeation ability. The resulting membrane was then characterized including tests of thickness, water uptake, tensile strength and membrane hydrophilicity. The results showed that the best composition of membrane occurred in the addition of 0.691 g of NaTPP proved byin creasing water uptake (150%), its highest mechanical strength and releasing the percentage of urea permeation by 44%.
Chitosan Succinate/PVA-PEG Membrane: Preparation, Characterization and Permeation Ability Test on Creatinine
Evaluation character of chitosan membrane-succinate / poly vinyl alcohol-poly ethylene glycol (PVA-PEG) were prepared in acetic acid solvent through a phase inversion method has been performed. The study began with the preparation of crosslinked chitosan compounds with succinic acid, followed by preparation into membrane by combining PVA-PEG. Character analysis of the resulting material using FTIR, EDX, TGA, water absorption test, tensile strength, membrane hydrophilicity. The ability of membrane permeation was tested against creatinine. The results showed that the succinate had reacted with chitosan. Chitosan modification through cross link and polymer alloys increases tensile strength and membrane strain of 1.7-2.5 x of pure chitosan membrane. In addition, the modified membrane also has higher water absorption and hydrophilicity values than the unmodified membrane, and this implies the ability of membrane-induced creatinine permeation. Permeable permeation values were 13.8% in chitosan, 24.84% on chitosan-succinate and 25% in chitosan-succinate / PVA-PEG. Chitosan-succinate membranes have the ability to use more than 4x repeated use.
Timber, its nature and behaviour
Preface. Acknowledgements. Chapter 1 - Structure of Timber. Chapter 2 - Appearance of Timber in Relation to its Structure. Chapter 3 - Mass Volume Relationships. Chapter 4 - Movement in Timber. Chapter 5 - Flow in Timber. Chapter 6 - Deformation Under Load. Chapter 7 - Strength and Failure in Timber. Chapter 8 - Durability of Timber. Chapter 9 - Processing of Timber. Index.