| In this study,the effects of alkali concentration,JFC concentration,and boiling time on the properties of bamboo fiber were studied.The optimized design of response surface was used to verify the optimal extraction process.Different proportions of non-woven fabrics and their composites were prepared by using extracted bamboo fiber(BF)and polypropylene(PP).The effect of bamboo fiber content on the mechanical properties of nonwovens and composites was studied,and the correlation between the properties of nonwovens and composites was analyzed.The effects of the modification process on the VOC release and mechanical properties of the composites were studied.This topic optimized the bamboo fiber extraction process through the response surface method.The optimal extraction process using response surface was 0.7%of alkali concentration,0.3%of JFC concentration and 2.5h of boiling time.The tensile strength at break of the obtained fiber was 386.25MPa,the friction coefficient was 0.206 and the diameter was 191.79?m,which was in agreement with the predicted value of the intensity of 405.08MPa,the diameter of 175.59?m and the friction coefficient of 0.191.The effects of bamboo fiber with different mass fraction on the properties of nonwovens and their composites were studied.The results showed that the strength of nonwovens decreased with the increase of bamboo fiber mass fraction.When the bamboo fiber mass fraction is 0,the maximum longitudinal tensile strength is 313.85N and the maximum transverse tensile strength is 63.96N.When the bamboo fiber mass fraction is 70%,the permeability of the bamboo fiber nonwoven fabric reaches the maximum,which is 2696.33mm/s.The thermal conductivity of nonwovens reaches the maximum value of 0.1073W/(m k)when the bamboo fiber mass fraction is 60%.When the bamboo fiber mass fraction is 70%,the composites have the most comprehensive mechanical properties,thermal conductivity and thermal diffusivity,the tensile strength is 37.18MPa,the tensile modulus is 3.88GPa,the flexural strength is 65.02MPa,the flexural modulus is 5.38GPa,shear strength of 9.21 MPa,thermal conductivity of 0.3539W/(m.k),thermal diffusivity of 0.3503mm2/s.The relationship between natural fiber components and VOC release was studied.A variety of modification techniques were used to study the reduction of VOC release from BF/PP composites.The results showed that the cellulose,lignin,hemicellulose have a relationship with the release of formaldehyde and cellulose,lipid were related to the release of acetaldehyde.The effect of adding 10%urea and 0.7%antioxidant is better than adding urea alone.The total release of VOC was reduced by 72.16%than that of unmodified,formaldehyde was reduced by 53.36%,and acetaldehyde decreased by 92.15%.The modification process of urea combine antioxidant on BF/PP composites was optimized.When the concentration of antioxidant is 0.9%,the effect of modification is the best.The concentrations of formaldehyde,acetaldehyde and VOC are 9.87E-08g-1/A,2.12E-08g-1/A and 1.21E-07g-1/A,which were 58.52%,90.70%and 74.09%lower than the unmodified composites respectively.At the same time,the flexural strength,flexural modulus and shear strength of the composites decreased with the increase of the concentration of antioxidant,reaching the maximum at the concentration of 0.3%,which were respectively 84.34MPa,7.50GPa and 8.36MPa.The mechanical properties were the lowest at the antioxidant concentration of 0.9%,which were 6.85MPa,6.04GPa and 7.62MPa respectively. |
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