Functional PVC Additives : Core-Shell Nanoparticle and Renewable Resource Plasticizers

Sammanfattning: Several functional poly(vinyl chloride) (PVC) additives were designed: PVC plasticizers made from renewable resources as alternatives to traditional phthalate plasticizers and core-shell nanoparticle-plasticizers with the aim to design an additive that can improve several mechanical properties simultaneously. Monomeric and oligomeric PVC plasticizers based of isosorbide and glucose were synthesized. Their structures and molecular weights were determined by SEC, NMR, FTIR and LDI-MS. PVC was blended with the different plasticizers and miscibility, mechanical properties and thermal properties of the blends were analyzed. PVC/isosorbide dihexanoate (SDH) films exhibited similar properties as PVC/diisooctyl phthalate (DIOP) blends. PVC films plasticized by oligo(isosorbide suberate) (OSS) and oligo(isosorbide adipate) (OSA) showed better thermal stability and higher mechanical strength, but lower strain compared to the PVC/DIOP and PVC/SDH blends. Glucose ester plasticizers with slightly different chemical structures were synthesized by applying different reaction times. Results revealed that the plasticization efficiency was improved by larger number of hexanoate units on the glucose ring. Altogether the glucose esters showed great potential as renewable PVC plasticizers.Core-shell nanoparticle-plasticizers were designed with the aim to simultaneously improve both the stiffness and toughness of the materials. Halloysite, kaolin and silicon dioxide nanoparticles were surface-grafted by poly(butylene adipate) (PBA). The surface-grafting was confirmed by FTIR and the amount of grafting was determined by TGA. PVC/nanoparticles binary blends and PVC/PBA/nanoparticle ternary blends were prepared by solution casting. The dispersion of nanoparticles in the PVC matrix, as observed by SEM, was remarkably improved by the surface-grafting. The tensile stress at break for the PVC films containing 5 wt-% surface-treated halloysite nanoparticles (St-Halloy-5) increased 15 % compared with the material containing same amount of untreated halloysite nanoparticles (untreated Halloy-5) films. The St-Halloy-5 films also exhibited 30 times higher strain at break values compared to untreated Halloy-5 films. The PVC films containing 5 wt-% surface-treated silicon dioxide nanoparticles (St-SiO2-5) exhibited remarkably higher strain at break values even though the strength was slightly lower compared to the material with same amount untreated SiO2 particles. The nanoparticle surface treatment also improved the mechanical properties of PVC/PBA/nanoparticle ternary blends. PBA/St-Halloy exhibited most obvious improvement compared to PBA/Halloy, the values increased more than 100% for both stress at break and strain at break The results show that the designed nanoparticle-plasticizers could simultaneous improve the stiffness and toughness of PVC materials.