Polyvinyl alcohol molecular structure

The actual experimental moduli of the polymer materials are usually about only % of their theoretical values [1], while the calculated theoretical moduli of many polymer materials are comparable to that of metal or fiber reinforced composites, for instance, the crystalline polyethylene (PE) and polyvinyl alcohol have their calculated Young s moduli in the range of 200-300 GPa, surpassing the normal steel modulus of 200 GPa. This has been attributed to the limitations of the folded-chain structures, the disordered alignment of molecular chains, and other defects existing in crystalline polymers under normal processing conditions. 

Rather recently, we have studied the solid-state structure of various polymers, such as polyethylene crystallized under different conditions [17-21], poly (tetramethylene oxide) [22], polyvinyl alcohol [23], isotactic and syndiotactic polypropylene [24,25],cellulose [26-30],and amylose [31] with solid-state high-resolution X3C NMR with supplementary use of other methods, such as X-ray diffraction and IR spectroscopy. Through these studies, the high resolution solid-state X3C NMR has proved very powerful for elucidating the solid-state structure of polymers in order of molecules, that is, in terms of molecular chain conformation and dynamics, not only on the crystalline component but also on the noncrystalline components via the chemical shift and magnetic relaxation. In this chapter we will review briefly these studies, focusing particular attention on the molecular chain conformation and dynamics in the crystalline-amorphous interfacial region. 

Highly polymerized polysaccharides with adjacent OH-groups in cis position, or even 1,3-diols, such as in polyvinyl alcohol react with borax (77, 78, 55, 77). The reaction was studied by measuring the increase in viscosity of the respective polymer. For the molecular structure a cross linkage of the borate tetrahedron to the polysaccharides has been suggested (77) (Fig. 12). 

In experimentel animals, methylcellulose injection leads to hypertension, due to extensive methylcellulose thesaurosis of the glomerular endothelium (Hall and Hall 1961). Comparable hypertension and nephrotoxicity have been produced by injection of polyvinyl alcohol (Hall and Hall 1965). The pathogenic effects depended more on molecular size than on chemical structure. Similarly, dogs and rabbits injected with pectin showed atheromatous changes and thesaurosis with foam cellular storage phenomena in spleen, liver, and kidneys (Hueper 1942). 

The relationship between the molecular structures of polymer materials for alignment layers and the bistability has been discussed by Myrvold [14]. Here, the bistabilities resulting from alignment layers made from polyethylene, polyfumarate esters, polyvinyl alcohol (PVA), polyacrylonitrile (PAN) and polyimide (PI) will be overviewed according to his studies. 

While the GFT pervaporation process for alcohol dehydration is based on a polyvinyl alcohol membrane of high hydrophilicity, polyion complex membranes have been recently developed to replace polyvinyl alcohol. The membrane material consists of polyanion (polyacrylic acid, molecular weight 5(X),(X)0, cross-linked with diepoxide) and polycation (PCA-107, the structure... 

Methyl methacrylate [CH2=C(CH3)COOCH3] is randomly copolymerized with maleic anhydride in the first stage, and the resulting copolymer is reacted with polyvinyl alcohol [CH2—CH—(OH)] in the second stage. Write down all of the chemical reactions involved and the molecular structure of the resulting polymers in both stages. 

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