3.1 Membrane porosity properties
A. The Effect of Pulp DP
Table 2 show the high DP of pulp (Exp. Code A) result in higher porosity (low density) and water permeability of membrane. As it is well known that the molecular weight of membrane polymer has a great effect on the membrane performance while molecular weight is depend on Degree of Polymerization which indicate number of repeat unit (monomer) in chain molecules. Polymer with high degree of polymerization will have longer chain and larger molecule compare to a polymer with low degree of polymerization. This long and large chain make more entangle occur between polymer chain but less chain mobility which cause NMMO difficult to break the entangled cellulose hydrogen bond during dissolution process result in less homogenous casting solution. Moreover this long chain and less chain mobility avoid polymer chain to arrange closer each other during coagulation process induce more porous part on membrane. Therefore when membrane composed of mixed cellulose DP the porosity is decrease due to the low cellulose DP can reduce this mechanism, however this tend to induce a bigger mean pore size since the low homogeneity in casting solution.
B. The Effect of Cellulose Concentration in casting solution
To obtain membranes with good performance, the polymer concentration of the casting solution usually is the key factor affecting the permeation rate, rejection and mechanical properties of membranes.[21] However this is restricted by process ability as well as production cost when higher concentration applied. In this work we use 11% as maximum concentration due to at 12% concentration the casting solution is too viscous so as during film casting process is difficult to obtain an eve...
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...asymmetric cellulose hollow fiber membrane Journal of Membrane Science 246 (2005) 157–165.
12. E. Maia, A. Peguy, S. Perez, Cellulose organic solvents. I.The structures of anhydrous N-methylmorpholine N-oxide and NmethylmorpholineN-oxide monohydrate, Acta Cryst. B37 (1981)1858.
13. W. Berger, M. Keck, B. Philipp, On the mechanism of cellulose dissolution in non-aqueous solvents, especially in O-basic systems,Cell Chem. Technol. 22 (1988) 387.
14. E. M. Andresen, G. R. Mitchell, Polymer 1998, 39, 7127.
15. H. Chanzy, M. Dube, R. H Marchessault, J. Polym. Sci.,Polym. Lett. Ed. 1979, 17,
16.
17.
18.
19.
20.F. Carrillo, X. Colom, J.J. Su~nol, J. Saurina; Structural FTIR analysis and thermal characterization of lyocell and viscose-type fibres;European Polymer Journal 40 (2004) 2229–2234
21. X. G. Jian, Y. Dai, G. H. He, G. H. Chen, J. Membr. Sci.1999, 162, 187
Ramachandria, C. T., Subramanyan, N., Bar, K. J., Baker, G., & Yeragani, V. K. (n.d.).
Scibd. N.p. Web. 17 Mar 2014. Beller, Michele.
Tadić, A., Wagner, S., Hoch, J., Başkaya, Ö., von Cube, R., Skaletz, C., ... & Dahmen, N. (2009).
Shinno, H., Matsuoka, T., Yamamoto, O., Noma, Y., Hikasa, S., Takebayashi, M., & Horigughi, J. (2007).
A group of polymer chains can be organised together in a fiber. How the polymer chains are put together is important, as it improves the properties of the material. The flexibility, strength and stiffness of Kevlar fiber, is dependent on the orientation of the polymer chains. Kevlar fiber is an arrangement of molecules, orientated parallel to each other. This orderly, untangled arrangement of molecules is described as a “Crystalline Structure”. A manufacturing process known as ‘Spinning’ is needed to achieve this Crystallinity structure. Spinning is a process that involves forcing the liquefied polymer solution through a ‘die’ (small holes).
Dialysis tubing is made from regenerated cellulose or cellophane, and is used in clinical circumstances to ensure that molecule have a filtered flow, and that larger solute molecules do not enter the dialysis tubing (Alberts, 2002). Like a cell membrane, dialysis tubing has a semi-permeable membrane, which allows small molecule to permeate through the membrane. Thus, the dialysis tubing mimics the diffusion and osmosis processes of the cell membrane (Alberts, 2002). Although the dialysis tubing has a semi-permeable membrane, which mimics a cell, its structure is different. The me...
According to osmosis theory as the concentration of the sucrose solution increases the particles water potential increases and becomes higher than the particles that are in the
Polman, H., Orobio De Castro, B. & Van Aken, M. A.G. (2008). Experimental Study of the
The first fiber was made-up from polyamide polymers were created in 1938 at USA and Germany. In USA the raw materials, used to create the polymer was adipic acid and hexamethylene diamine and since both chemicals contain 6 carbon atoms the new polymer was named polyamide 6.6. In Germany caprolactam was polymerised to produce a different fiber known as polyamide 6. [4]
These compounds have their structures range from linear to highly branched compounds. Examples of storage polysaccharide include, starch and glycogen and structural polysaccharide include cellulose and chitin. Cellulose is a significant polysaccharide as it is the most abundant organic compound in the world. It is made up of the sturdy cell wall that surround plant cells making plant stems, roots, leaves and branches strong. Chewing of plant produce such as salad takes a lot of time and strength due to the effect of cellulose. The rigid structure gives support to the plants position. Additionally, the active nature enables the existence of the paper, lumber and cotton fabric. It is due to this strength that cellulose is used in large number of synthetic products such as carpet thickening and agents in shampoo (Salter, Tucker, & Wiseman,
Link, B. G., Struening, E. L., Neese-Todd, S., Asmussen, S., & Phelan, J. C. (2001). The
Figure. 2 gives a brief summary of the applications of biomass-derived degradable polymers. Nowadays, there are tremendous interest in research and using of biopolymers in packaging, civil engineering, biomedical and automotive mystery
present at all times but it must retain some of them. All plant life on Earth benefits from the ability of water to make a hydrogen bond with another substance of similar electronegative charge. Cellulose, the substance that makes up cell walls and paper products, is a hydrophilic substance ("water-loving"). It interacts with water but, unlike other hydrophilic substances, it will not dissolve in it. Cellulose can form strong hydrogen bonds with water molecules. This explains why a paper towel will "wick" water upwards when it comes in contact with it.
V. Amarnath, D. C. Anthony, K. Amarnath, W. M. Valentine, L. A. Wetterau, D. G. J. Org. Chem. 1991, 56, p. 6924-6931.
Starch is often converted to commercial products of glucose, maltose syrups, and is a major enzyme application. Enzymes break down the polysaccharides into multiple sugars. They help to improve starch purity and clarity, creating greater abstractionyields, and removal of fibers. Pectin and Celluloseare insoluble substances found in plant cell walls. Pectinase and Cellulase are used to break down pectin and cellulose respectively. It helps to clear fruit juice, decrease viscosity, and create a good consistency and texture (Thakur,