Despite key advances in demonstrating the feasibility of catalytic conversion of plastic wastes into high value-added chemicals, fundamental understanding on the interactions of polymers and catalytic materials is currently lacking. To enable highly efficient catalytic processes, it is critical to understand and engineer polymer-porous solid interactions. This thesis addresses this knowledge gap. There has not been a general approach to characterize polymer-solid interfacial properties quantitively. Although contact angle measurement is a powerful technique to quantify the polymer-surface interactions, the traditional sessile droplet method for a normal liquid cannot be easily applied to polymers. In our research, capillary rise infiltration of polymer into nanoparticle packing is used to study the polymer dynamics and polymer-solid interactions. We measure the rates for capillary infiltration of polymer, such as polystyrene (PS) and polyethylene (PE), into disordered packings of silica nanoparticles that are modified by atomic layer deposition (ALD) with sub-monolayer and monolayer coverages of TiO2, WO3, and CaCO3. Infiltration times depend strongly on the size and surface composition of nanoparticles. The confined infiltration rates measured as a function of surface-chemistry composition are used to calculate contact angles and interfacial energies for PS and PE via the Lucas-Washburn model. To understand the effect of composition, we perform microcalorimetry measurements with n-hexane and benzene on ALD-modified SBA-15. Our results have shown a strong inverse correlation between n-hexane adsorption and PE-solid interfacial energies and between benzene and PS-solid interfacial energies. Molecular dynamics and density functional theory calculations performed by our collaborators show strong agreement with our experimental results. Confinement of polymers in nanopores also affect the polymer properties. Prior research in this area has been limited to pore that are greater than the typical size of polymers, ~ 20 nm. In our research, the confined viscosities of polymers are determined from the infiltration times via the Lucas-Washburn equation. The effective viscosity is proportional to 1/pore size in the range from 2 to 20 nm. Based on our observation on the effective viscosity of polyethylene in extreme nanoconfinement, we have proposed a generalized formalism to describe polymer transport dynamics in nanopores. Another important physical property of polymers that may be significantly impacted by confinement is their phase transition temperatures such as melting points of PE. The melting point of PE decreases as the pore size decreases and reaches a saturated value at 22 C below the bulk melting point. At this point, the pore size is smaller than the minimum crystalline domain of PE. The thesis also introduces an outlook on the investigation of hydrogen solubility in polyethylene within porous material, which is crucial in many catalytic reactions involved with hydrogen using quartz crystal microbalance. Overall, this thesis contributes substantially to the field of polymer physics in porous media, paving the way for future innovations in material science and engineering of nanocomposites and polymer upcycling.