| Lignin is a abundant renewable resource.The high value utilization of lignin has become one of the important directions of lignin application research.Alkali lignin mainly comes from the by-products of pulping and papermaking.Its structure is more complicated,and it contains more polar functional groups.Alkali lignin is obviously incompatible when blended with polymer materials with lower polarity or large structural difference.The interface compatibility of blends has typically been studied by characterization from the viewpoint of chemical structure,by using the change of thermal and mechanical properties to speculate about the mutual relationship between the two components,or by using the swelling method to analyze qualitatively the interaction between the two components,lacking direct qualitative evaluation system.This study attempts to modify alkali lignin and ABS to make the two better compatible according to their surface and interface properties,so that the blended materials have better performance.In addition,the solubility parameter and material properties were introduced to characterize quantitative,and the relationship models between the solubility parameters and mechanical properties and surface properties of blends were established and verified further.The research results are as follows:Inverse gas chromatography(IGC)was used to measure the compatibility of alkali lignin and ABS resin.By using the Schultz method,N-alkanes were chosen as the neutral probes to calculate the dispersive surface free energy(?sD)of alkali lignin and ABS resin.Based on Good-van Oss method,the specific surface free energy(?sSP)of alkali lignin and ABS were culculated with the acidic probe of dichloromethane and the basic probe of toluene.The results showed that ?sD and ?sSP of alkali lignin was irregular at different temperatures,but ?sD and ?sSP of ABS varied linearly with temperature.The compatibility of alkali lignin/ABS blends was predicted by Flory-Huggins interaction parameter(?AB).The value of ?AB was about 0.29,which indicated that the compatibility of alkali lignin and ABS was poor,and further modification was needed to improve the compatibility.In alkali lignin/modified ABS system,the Hansen solubility parameters and related thermodynamic parameters of alkali lignin/modified ABS blends were measured by IGC.Hansen solubility parameters of blends containing 0,10,20 and 30 wt%alkali lignin were 21.26,18.85,20.30 and 18.94(J/cm3)0 5 at room temperature,respectively.A relationship was established between Hansen solubility parameter(?2)and tensile strength,which fitted the binomial relationship:Y=12.58X2-496.32X+4958.54(18.85?X?21.26),where X is Hansen solubility parameter and Y is tensile strength of the blend.The relationship between Hansen solubility parameter(?2),contact angle and surface tension were also established and fitted the binomial relationship:Y=4.67X2-182.43X+1861.73 and Y=-2.91X2+113.74X-1053.69(18.85?X?21.26),where X is Hansen solubility parameter and Y are contact angle and surface tension of the blend,respectively.The correlation coefficient and further experimental validation show that the solubility parameters of blends are related to the change of these properties.In acetylated alkali lignin/ABS system,the Hansen solubility parameters and related thermodynamic parameters of acetylated alkali lignin/ABS blends were measured by IGC.And the correlation between compatibility and properties of acetylated alkali lignin/ABS blends were quantitatively studied.The relationship models were established between the solubility parameter(?2)and tensile strength,contact angle and surface tension,respectively.The correlation coefficient and further experimental validation show that the solubility parameters of blends are related to the change of these properties.In alkali lignin/ABS system,there is also a strong correlation between the solubility parameters and surface properties of blends with different proportions alkali lignin.The relationship models were also established and verified.T he addition of alkali lignin also has some effect on the flame retardancy of alkali lignin/ABS composites.With the addition of lignin,the oxygen index of the composites increased,not meeting the application requirements yet.When 15%flame retardant masterbatch and 30%alkali lignin were added,the oxygen index of the composites was up to 28.0%,which had good flame retardancy. |
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