Epoxy will not bond polyethylene and polypropylene materials. Neither will polysulfide adhesives such as BoatLIFE Life-Calk, or polyurethane adhesives such as 3M 5200 or Sika-flex.
Methacrylates are generally the type of adhesive to use to bond these dissimilar plastics. An example would be 3M Scotch-Weld DP 8005 Structural Plastic Adhesive. Its two-part structural formulation effectively bonds low surface energy plastics such as polyethylene and polypropylene with other materials, without pre-treating the surface.