Developing　high-performance　polymer　nanocomposites　with　outstanding　heat　resistance　and　high　strength,　and　superior　ductility　is　vital　for　their　practical　applications.　However,　it　is　a　great　challenge　to　achieve　simultaneous　improvements　in　the　strength　and　ductility　due　to　the　presence　of　antagonistic　mechanisms　in　the　both　parameters.　Nanoconfinement　structure　affording　heat　resistance　and　high　strength,　and　good　extensibility　is　inspired　by　the　natural　world,　such　as　spider　web,　silkworm　net,　and　honeycomb　consisting　of　three-dimensional　networks　generated　by　vast　hydrogen　bonds.　Here,　we　reported　the　methods　of　oxygen-free　fast　drying　assisted　solution　casting　and　melt　blending　for　fabricating　advanced　ultrathin　two-dimensional　(2D)　titanium　carbide　(Ti3C2Tx)/polypropylene　nanocomposites　with　significantly　enhanced　initial　degradation　temperature　(79.1　°C　increase),　tensile　strength　(35.3%　increase),　ductility　(674.6%　increase)　and　storage　modulus　(102.2%　increase).　The　thermal　stability　and　mechanical　properties　improvements　induced　by　Ti3C2Tx　nanosheets　are　superior　to　those　of　similar　2D　nanomaterials,　such　as　graphene,　molybdenum　disulfide,　montmorillonite,　layered　double　hydroxide,　and　even　1D　carbon　nanotubes　because　of　the　combination　of　H-bonds　induced　nanoconfinement　structure　with　the　physical　barrier　effect　of　ultrathin　Ti3C2Tx　nanosheets.　This　work　provides　a　facile　nanoconfinement-inspired　strategy　for　the　design　of　thermally　stable,　mechanical　strong　and　ductile　polymer　materials　and　a　paradigm　for　broadening　the　application　of　2D　MXenes　in　polymeric　materials.　©　2019　Elsevier　B.V.