A new adhesive sealant with improved mechanical properties has been prepared by blending a sealant based on poly(dimethy1 siloxane)-(PDS) with poly(viny1 ct$oride)-(PVC) and Kraft lignin (L). During this study, California redwood was used as substrate. Two commercial primers were also used to examine their effects on the adhesion of joints. By adding a small amount of L, the modulus of the sealant baszd on PDS + 10% PVC is improved. The application of primers to the wood substrate has significantly improved the adhesion of PDS, PDS + 10% PVC and PDS + 1070 PVC + L polyblends. Improvement in adhesion increased the stress-strain values of the joints. Statistical inference of the experimental results are also discussed.