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Polyhydroxyalkanoates irradiation grafting maleic anhydride , isoprene research

Author: YeHeRong
Tutor: HuPing
School: Tsinghua University
Course: Materials Science and Engineering
Keywords: Poly -β -hydroxybutyrate Radiation grafting Maleic anhydride Isoprene Thermal stability
CLC: O633.4
Type: Master's thesis
Year: 2005
Downloads: 95
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Abstract


This paper explores a method for improving poly-β-hydroxybutyrate (PHB) and its copolymers (PHBV) thermal stability new method, which uses 60 COγ ray irradiation PHB and (PHBV) for maleic anhydride (MA) graft, and in the work of this group on the basis of previous irradiation grafting PHB isoprene carried out further studies. By 1 HNMR, 13 CNMR spectra that showed that MA monomer was successfully grafted on to the PHB. TGA tests showed that irradiation grafted products significantly improved thermal stability, as the graft was 0.52% of the PHB-g-MA improved thermal decomposition temperature of the sample 36 ℃, the graft was 0.85% of PHBV-g-MA Thermal decomposition temperature of the samples increased 70 ℃. DSC studies show that the melting temperature of irradiation grafted products and crystallization temperatures were reduced. Furthermore, the introduction of polar monomers maleic anhydride, XRD results show that the crystallinity of the product reduces the graft, while the hydrophilic graft samples increased. Changes on the irradiation conditions have a significant impact on the graft product, MA in the reaction system, the monomer concentration, the product of grafting, the viscosity-average molecular weight and the thermal decomposition temperature with a weak rise; increase in total dose that significantly lower viscosity average molecular weight, MA hinder the introduction of irradiation may degrade significantly the extent of reaction; as the radiation dose rate increases, the reaction product of grafting rate and viscosity average molecular weight is increased. Irradiation reaction system in the amount of inhibitor Cu (NO 3 ) 2 after irradiation grafting on PHB isoprene work carried out further research, experimental results show that adding Cu (NO 3 ) 2 after the thermal stability and mechanical properties are further improved. In the reaction system by adding isoprene monomer (IP), but did not join inhibitor Cu (NO 3 ) 2 radiation grafted samples, the thermal decomposition temperature no increase than pure PHB. In the reaction system by adding isoprene monomer (IP), but also added Cu (NO 3 ) 2 and found that irradiation grafting grafting products While the reduced, but the thermal decomposition temperature is greatly increased. Adding an appropriate amount in the reaction system inhibitor Cu (NO 3 ) 2 radiation grafted samples PHB-g-PIP100Cu and PHB-g-PIP19Cu significantly better mechanical properties in other samples, slightly elevated tensile strength, enhanced toughness, flexural strength and modulus were also significantly increased.

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CLC: > Mathematical sciences and chemical > Chemistry > Polymer chemistry ( polymer ) > Miscellaneous Chain Polymers > Containing two or more different atoms of the polymer chain
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