Title : Green and Highly Efficient method for Improving Interfacial behavior of Bamboo Fiber Reinforced Poly-?-hydroxybutyrate Biocomposites using Mussuel-Inspired Polydopamine with Biological Enzyme-catalyzation
As the “green” production trend has increased worldwide, it is popular and necessary to manufacture durable, eco-friendly and sustainable materials such as plant fiber reinforced biodegradable thermoplastic composites. However, the poor interfacial compatibility between plant fibers and matrices is a major problem to overcome. In order to improve interfacial compatibility in biocomposite made of bamboo fiber (BF) and biodegradable Polyhydroxybutyrate (PHB), this work, Inspired by mussel super adhesion and the “green enzyme” concept, creates a facile, highly efficient and enviromental friendly route based on laccase-catalysed dopamine in situ polymerization under natural environment. The results of the study indicate that polydopamine was not just deposited on the surface of BF by laccase catalysis but also chemically grafted onto BF lignin, forming a more stabilized coating. Meanwhile, the BF’s natural weak acidic environment keeps it from undesired chemical degradation during the abovementioned modification. Optimal composition of biocomposite with BF treated by polydopamine under 1U/ml concentration of laccase shows improvement on the impact strength, tensile strength, tensile modulus, bending strength, and modulus of elastic by 33.93%, 9.27%, 31.74%, 11.76%, and 12.92%, respectively, compared to the unmodified PHB biocomposite. In addition, the polydopamine modified BF with laccase enhances the thermal stability of the fiber and its biocomposite. Moreover, modification of BF via laccase-catalyzed polydopamine is superior to the conventional method of polydopamine under alkaline condition regarding the interfacial compatibility improvement of BF and PHB. Overall, this work provides an insightful understanding of the mechanism and benefits of laccase-catalyzedf polydopamine modification of BF in a natural environment and contributes to the efficient and environmentally friendly utilization of polydopamine for fabricating high-performance plant fiber reinforced composites.
What will audience learn from your presentation?
Bamboo fiber(BF) reinforced Polyhydroxybutyrate(PHB) can reduce the utilizing cost of PHB and produce a promising biomass composite with durable and better mechanical performance, promoting the PHB in a sustainable material manufacturing that well protect the environment. However, this could only be achieved after overcoming the interface incompatibility between the hydrophilic surface of BF and the hydrophobic surface of PHB. Inspired by the natural mussel super adhesion, the in situ polymerization of dopamine onto plant fiber has become a desirable and highly effective surface modification strategy to promote interfacial adhesion of BF reinforced thermoplastics in recent years. Despite the advance of dopamine adoption in modifying BF surface, the convention method of in situ polymerization of dopamine onto BF under an alkaline environment (pH=8.5) could involve some significant drawbacks. Specifically, the process method has a long duration (more than half a day for oxidation) and a large alkali consumption that not only has an adverse effect on the alkali-sensitive BF, but also produces polluted spent alkaline solutions after treatment.
My work proposed a more facile, highly efficient, and environmentally friendly route of in situ laccase-catalyzed polymerization of dopamine onto BF. Compared with the conventional method, this strategy improves the compatibility of PHB and BF interface more effectively, and it successfully solves the technical deficiency of dopamine utilization under the alkaline environment in the BF surface modification.
Furthermore, the milled wood lignin (MWL) of BF was extracted for further investigation of the modification effect of lignin under pure laccase catalysis, laccase-catalyzed polymerization of dopamine grafted lignin, and alkaline environment, respectively. These findings provide more valuable support for revealing the mechanism of in situ laccase-catalyzed graft copolymerization of dopamine onto the BF surface lignin. And it may help the audience deeply understanding how poly-dopamine coat on the BF surface under laccase catalysis, which may give them a new inspiration for their future develop on adhesives for plant based composite.