Study On Bamboo Fiber Reinforced P34HB Composites And The Thermal Stability Of P34HB

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P34HB) is the latest generation of PHAbiological macromolecule. Because of its biosynthesis, biodegradability and wellcomprehensive, it has been applied in the field of biological medicine, packaging andagriculture, etc. However, P34HB is insufficient in crystallization, mechanical properties andthermal stability. So, those defects become the most vital factor which are severely hamperedthe development and application of P34HB.In this paper, bamboo fiber enhanced P34HB composites were prepared. We wereprepared modified BF through alkali treatment, maleic anhydride modified and silanecoupling agent modified, respectively. The results showed that the mechanical propertiespeaked when BF was treated in5wt%NaOH solution to deal with8h, and ATBF loadingwas10phr. At this point, the tensile strength and flexural strength were increased by58.63%and46.22%compare to P34HB, respectively. Fiber analysis results show that draw ratio ofBF and cellulose content were increased after alkali treatment, those factors were beneficial tothe reiforement result of BF. DSC showed that BF is a good nucleation agent for P34HB, so itcan improve the crystallization properties of P34HB composites. TGA illustrated that thermalstability of P34HB/BF composites were enhanced.In this paper, we made a systematic study of thermal stability of P34HB compositeswhen addition in different fillers. We found that that EMMT can improve the thermal stabilityof P34HB significantly, when the addition content is5phr, the thermal degradationtemperature of composite is reach to270.4℃, improved by nearly40℃campare to pureP34HB (231.6℃), and vicat softening point is increased as well as. TGA-IR showed thatEMMT can improve the thermal stability of P34HB, but it did not change its degradationmechanism. DSC tested indicated that EMMT is a good nucleating agent for P34HB havenucleation effect, when the addition content reached5phr, Tc was increased from70.8℃to93.2℃, improved by22.4℃. TEM analysis found that EMMT was uniformly dispersed in thematrix, and dispersed scale was between20nm to70nm. With material mechanics performance, when EMMT loading was5phr, the comprehensive performance of EMMTP34HB/EMMT nanocomposites was the best.Degradation analysis showed that the P34HB and its composites were very stable inphosphoric acid solution (pH=1.3). But in NaOH solution (pH=13), P34HB and itscomposites wer easily degraded and the degradation rate were quickly. The propertiesdegradation samples were not changed after acid treatment. However, because of P34HBmolecular chain ester base was sensitive to alkali, so its crystallization properties and thermalstability were decreased after NaOH solution treatment.