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In this work, a bio-based material (CGP) is obtained by combing chitosan, gelatin and polyvinyl alcohol through a simple solution mixing to simultaneously address polylactic acid film (PLA)' flammability and poor barrier, toughness and antibacterial properties by soaking. The results of open fire testing show that modified PLA films can effectively prolong the combustion time, improve the thermal stability and reduce the release of heat in the cone calorimeter test. For the PLA sample after soaking for 5 times (PLA-5) in particular, it can reduce the peak heat release rate (pHRR) and total heat release (THR) values to 85.8 kW/m2 and 1.3 MJ/m2 from the values of 129.5 kW/m2 and 1.8 MJ/m2 for PLA, respectively. Structural analysis suggests that CGP primarily operates in the condensed phase by forming physical barriers. Meanwhile, the modified PLA films can exhibit superior barrier effects, which indicate the oxygen transmission rate value of PLA-5 decreases to 0.9 cm3/(m2·day) from the 392.5 cm3/(m2·day) of raw PLA film. Moreover, the PLA-5 also have excellent toughness (the value increased to 200.5 % from 31.0 %) and persistent antibacterial effects (it still has 100 % sterilization after 500 days). • A bio-based multi-functional coating (CGP) was fabricated and coated on the PLA film. • CGP (average thickness was 1.26 μm) could as a fire shield for underlying substrates. • The flame-retardant mechanism was deeply studied of PLA-5. • PLA-5 strain was obviously enhanced vis-à-vis PLA, and the reason was deeply studied. • CGP can endow PLA with excellent properties of barrier and persistent antibacterial. [ABSTRACT FROM AUTHOR]

Ethylene vinyl acetate copolymer (EVA) is widely applied in many important fields, but its broader utility is impeded by its flammability. To address this problem, the pre-acidified kaolinite (AKaol) by sulfuric acid was further dealt with TiO 2 loading and Zn2+ doping to obtain Zn/TiO 2 @AKaol to improve the flame retardancy and smoke suppression of EVA composites containing intumescent flame retardants (IFR) typically. The results showed that the addition of 1 wt% Zn/TiO 2 @AKaol improved the flame retardancy and reduced the smoke release of EVA/IFR composite. The limiting oxygen index (LOI) value of the EVA/IFR composite containing Zn/TiO 2 @AKaol increased to 32.7 % from 27.3 % of EVA/IFR composite. In the cone calorimeter test (CCT), the peak heat release rate (pHRR) and total heat release (THR) values were reduced to 297.5 kW/m2 and 98.8 MJ/m2 from the 409.9 kW/m2 and 109.3 MJ/m2 of EVA/IFR composite, respectively. Meanwhile, the values of total smoke production (TSP) in the CCT and smoke density tests in building materials were reduced to 13.5 m2 and 33.39 % of EVA/IFR/Zn/TiO 2 @AKaol composite from 18.4 m2 and 63.91 % of EVA/IFR composite, respectively. Based on the mechanism analysis, it was proposed that Zn/TiO 2 @AKaol not only promoted the production of P· in advance, but also increased a cross-linked structure char in the condensed phase to achieve flame retardancy and smoke suppression of EVA composites. [ABSTRACT FROM AUTHOR]