Film formation process of natural rubber latex particles: roles of the particle size and distribution of non-rubber species on film microstructure

•The presence of small rubber particles enhances the film-forming efficiency of rubber film.•The boundaries of rubber particles in latex-cast films remain intact after film-forming.•The membrane substances are responsible for creating 3D supporting frameworks.•The membrane components-derived networks are destructed by toluene dissolution.•The latex-cast films perform better in mechanical strength than the solution-cast films do.