Studies On The Structure And Properties Of Complex Materials From Poly(4-vinylpyridine) Or Derivatives And Natural Macromolecule

It is well known that miscibility is poor between many polymers blend. Blend miscibility is very important for properties of materials. So many researchers have been interested in study of miscibility between many polymers blend. The miscibility of most polymer pairs found so far is caused by intermolecular specific interactions, which have been testified by thermodynamics and experimentation. The specific interaction is hydrogen bonding, dipole-dipole forces, and charge-transfer. Many reports found that secondary forces with no covalent bonding could be produced between complementary polymers in solution, which induce complex, association, aggregate or cluster. Because the complex is produced, some especial behavior is shown in macromolecular solution, such as aggregate, sol, gel, liquid crystal and so on. And the properties of complex aggregate are frequently different that of components. With development of life sciences, many researchers found that the secondary force is of importance in biologic system; the biologic functional achievement depended on complex of macromolecule, so scientists have been interested interaction between macromolecule. In recent years, many scientists profoundly studied the secondary force, complex condition, structure, and properties of complex systems. It is very important for scientific study and application.Poly(4-vinylpyridine) is a functional polymer. Poly(4-vinylpyridine) undergo typical reaction of monomeric pyridine. They react with alkyl halides to give quaternary salts and with hydrogen peroxide give N-oxides. It also can be react with other halide, such as chloroactic acid, ethyl cholroacetate, cholroethyl amide, cholroethyl alcohols, and so on. So some functional groups are linked with polymer. Poly(4-vinylpyridine) and derivatives has ability to strongly kill bacteria and affinity for microorganism, and possesses a good gas permselectivity. The blend materials with Poly(4-vinylpyridine) and derivatives could possess especial interaction, which will show some new function and application.Natural macromolecule such as chitosan, konjac glucomannan, alginate and lignin, possess many functional groups. They, specially, with its many reactiveactivated groups, can form strongly interaction with many polymers, which has been improved and modified the physical properties of the pure polymers. Scientists have been of interest application of natural macromolecule in medicine, environment and pervaporation membranes. Because they have -NH2 and -COOH, respectively, they could be modified by link, copolymer, blend and ionization. Among the membrane materials, the hydrophilic polysaccharide polymers such as chitosan and alginate have gained special interest because they have shown the highest flux and separation factors of any hydrophilic materials tested for the pervaporation dehydration.Because PVP is insoluble in solution, and many natural polymer is soluble in solution, so the studies on PVP / natural polymer blends are restricted. Based on above limit, we undertake study on blend between poly(4-vinylpyridine) and derivatives and natural macromolecule such as chitosan, konjac glucomannan, alginate and lignin. Derivatives derived from Poly (4-vinylpyridine), possess some functional group, which could enhance intermolecular specific interactions and improve blend miscibility. We can effectively adjust the structure and properties of blend by designing different functional groups and blend ratio. Few reports are found about this study in references. We purchase the relationship based structure, properties and function, which would provide important scientific proofs for the further research and development of new complex materials based on synthetical polymer and natural macromolecule. Therefore, this thesis exhibits scientific significance and prospects of application.The creative points of this thesis are as the follow. Based on principle of blend and molecular design, we used reagent possessed specific functional group to modify poly (4-vinylpyridine), which boosted up miscibility between them and natural polymer. A series of new blend materials from poly(4-vinylpyridine) or derivatives and lignin, chitosan, alginte, konjac glucomannan were prepared. The structure and properties of new materials were primarily confirmed. The results exhibit that the physical link from lignin and poly(4-vinylpyrindine) was produced, but the electrostatic link from chitosan or alginate and quarternized poly(4-vinylpyridine) containing zwitterions structure units were produced at well-proportioned blend ratio, which bring appreciable improvement in themeasured tensile strength and breaking elongation.The main research contents and conclusions are described as the follows. (1) A series of blend films were prepared by blending 2wt% chitosan acetate water solution and 4wt % quaternized QPVP in aqueous solution by casting method for the first time. The results from thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and tensile test indicated that the mechanical properties in the dry state and thermal stability are superior to those of chitosan film and achieve their maximum when the weight ratio of chitosan to QPVP is 9: 1. The results from wide-angle X-ray diffraction (WXRD) showed that the crystallinity of the blend films first decrease and then increase with the increase of QPVP content. All results lead to the conclusion that a strong adhesion at the interface exists between chitosan and quaternized QPVP in the blends prepared from solution. An intermolecular complex, or an orderly arrangement of two or more phase, caused by the interaction of intermolecules was confirmed by the results of SEM and IR and WXRD. The enhancement of mechanical properties and thermal stability may be due to strong adhesion existing between these polymers.(2) A series of novel blend films were prepared through casting the mixture of 2wt% konjac glucomannan and 4wt% quaternized poly (4-vinyl-N-butyl) pyridine (QPVP) for the first time. The good miscibility between konjac glucomannan and quaternized poly (4-vinyl-N-butyl) pyridine, when the content of QPVP was less 30% or in excess of 70%, was confirmed by the results of SEM and WXRD. The thermostability and tensile strength of the films in dry state were reduced with the increasing content of quaternized poly (4-vinyl-N-butyl) pyridine. The maximum value of 12.74% tensile break elongation was reached when the content of QPVP was 30%. The structure analysis indicated that the electrostatic interaction of quaternized poly (4-vinyl-N-butyl) pyridine (QPVP) and konjac glucomannan impaired the partial hydrogen bond interaction of KGM, which caused the easily sliding of the KGM molecular chains or the stretch of the KGM molecular chains. Following the weight of QPVP increasing, more and more electrostatic interaction destroyed the hydrogen bond interaction, which caused the phase separation. Results from the films at KGM-2 coating preservation experiment to litchi showedthat this blend film had water-holding ability and the ability to strongly attack bacteria and promote an affinity for microorganisms. The fruit weight loss rate and rot rate both decreased by various values. The novel polymer blends could be used preservative films.(3) A series of novel blend films between poly(4-vinylpyridne)(PVP) and lignin were prepared by casting method for the first time. The results from SEM and DSC indicated that PVP is miscible with lignin due to intermolecular hydrogen bonding between the hydroxyl of lignin and the pyridine ring of PVP over the entire composition range measured. The IR spectra of the blends proved that hydrogen-bonding interaction occurred between PVP and lignin. The glass transition temperature of these blends increased with an increase of lignin content, which indicates that these blends are able to form a miscible phase due to the formation of intermolecular hydrogen bonding between the hydroxyl of lignin and the pyridine ring of PVP. The thermostability of these blends decreases with the increase of lignin content. Initially, an appreciable increase in the measured tensile strength was achieved with a lignin content of 15%, and the maximum value of 33.03MPa tensile strength was reached. At a 10% lignin incorporation level, the blend exhibited its maximum value of 9.03% strain. When the threshold in lignin content for blends exceeded the range, the tensile behavior of these blends became poorer because of micro-domains of lignin.(4) Novel Polyion complexes films of chitosan and Quarternized Poly (4-vinylpyridine) Containing zwitterion structure units were prepared by casting method for the first time. Their structure and properties were studied by infrared (IR), wide-angle X-ray diffraction (WXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), tensile tester, and swelling measurements. The results indicated that polyion complexes occurred between chitosan and Quarternized Poly (4-vinylpyridine) Containing Zwitterion Structure Units because of the electrostatic interaction between the carboxyl groups (-CH2COO) of QPVP and the protonated amine groups (-NHj*) of chitosan. The thermostability of these blends decreased with the increase of Quarternized Poly (4-vinylpyridine) content, which suggested that QPVP had destabilizing effect on chitosan. The existence of QPVP in the blends might aggravate the degradation ofchitosan at high temperature. It indicated that the electrostatic interaction of polyion complexes could induce the fall of thermal stability. Initially, appreciable improvement in the measured tensile strength and breaking elongation were achieved with a Quarternized Poly (4-vinyl-N-carboxymethylpyridine) content of 30 %, the maximum value of 46.65MPa tensile strength and 25.67 % breaking elongation were reached, respectively. The enhancement of tensile strength and breaking elongation may be due to a greater number of chitosan / QPVP ionic linkages per each chain. An increase of QPVP weight upon to 50% increases the degree of swelling in the distilled water, which could be attributed to the formation of the polyion complexes between chitosan and QPVP and be due to an introduction of quaternary ammonium groups which have a higher affinity for the water molecule. Especially, It was worth noting that the polyion complex produced partially in chitosan bulk, with introducing quarternized poly(4-vinyl-N-carboxy-methylpyridine) containing zwitterion structure units, can improve the mechanical properties of polyion complex and swelling degree, which could be used a hydrophilic membrane with the potential for use as a hydrophilic membrane of the types used in membranes distillation and osmatic distillation, and increase the separation factor.(5) Novel blend films of alginate and quarternized poly (4-vinylpyridine) containing zwitterion structure units were prepared by casting method for the first time. Their structure and properties were studied by Fourier transform infrared (FIR), wide-angle X-ray diffraction (WXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), tensile tester. The results indicated that electrostatic interaction occurred between alginate and quarternized poly (4-vinylpyridine) containing zwitterion structure units because of the electrostatic interaction between the quarternized pyridine ring of QPVP and the carboxyl groups (-CH2COO) of alginate. The thermostability of these blends decreased with the increase of quarternized poly (4-vinylpyridine) content, which suggested that QPVP had destabilizing effect on alginate. The existence of QPVP in the blends might aggravate the degradation of alginate at high temperature. It indicated that the electrostatic interaction could induce the fall of thermal stability. Initially, appreciable improvement in the measured tensile strength and breakingelongation were achieved, the maximum value of 53.5MPa tensile strength was reached when the content of QPVP was 30 %, and the maximum value of 16% breaking elongation were reached when the content of QPVP was 20%. The enhancement of tensile strength and breaking elongation may be due to the electrostatic interaction. Especially, It was worth noting that the polyion complex produced partially in alginate bulk, with introducing quarternized poly(4-vinyl-N-carboxymethyl- pyridine) containing zwitterion structure units, can improve the mechanical properties of blend films. Swelling experiments indicated that QPVP could effectively improve the penetrability of water in blend films.The results of the foundation researches dealing with the complex materials between poly(4-vinylpyridine) and derivatives and natural macromolecule have provided important scientific proofs for further research and development of complex materials of synthetical polymer and natural macromolecule. The modification by blending poly(4-vinylpyridine) and derivatives and natural macromolecule provided novel membranes for separation science and technology. Therefore, this thesis exhibits scientific significance and prospects of applications, and well accords with the target of our country and the strategy of sustainable development.