Direct surface modification of polymer fibers and films by surface-initiated polymerizations has been investigated. The introduction of initiating sites on the polymer materials and successive polymerization produce surface-tethered polymer chains on the polymer surface. The surface-selective modification controls the surface properties such as wetting, lubrication and anti-fouling without sacrificing the bulk performances. Researches on grafting polymer chains to five types of polymers, poly(methyl methacrylate)-based copolymer, Br-containing polyolefins, poly(butylene terephthalate), poly(vinylidene fluoride-co-trifluoroethylene) and poly(ether-ether ketone) are reviewed.
Polymer Surface and Interfaces
Preparation of polymer brushes with well-controlled stereoregularity and evaluation of their functional properties
Preparation of Polymer Brushes with Well-Controlled Stereoregularity and Evaluation of Their Functional Properties High-density poly(methyl methacrylate) (PMMA) brushes with well-controlled stereoregularity were prepared using a surface-initiated living anionic polymerization method in the presence of a Lewis acid. A molecular weight range from 6 K to 400 K with a narrow polydispersity index (PDI) was obtained. Grazing incidence wide-angle X-ray diffraction measurements indicated that the polymer brushes formed a helical structure approximately 1 nm in diameter and consisting of encapsulated functional molecules or polymers, leading to the formation of inclusion complexes or stereocomplexes.
The liquid crystalline (LC) rod-like mesogens preferentially orient normal to the substrate plane due to the excluded volume effect (homeotropic alignment) in side-chain liquid-crystal (SCLC) polymers free-standing films. For in-plane alignment, a homeotropic orientation is unsuitable because the mesogens are in a direction opposite to the in-plane directions. This review focuses on new approaches to induce a random planar orientation in SCLC polymer systems by interface and surface molecular design utilizing a high-density polymer brush structure and surface segregation structures of block copolymers.
Structure-property relationships of polypropylene-based nanocomposites obtained by dispersing mesoporous silica into hydroxyl-functionalized polypropylene. Part 1: toughness, stiffness and transparency
Nanocomposites composed of mesoporous silica (MPS) materials with various porosity structures (two types of SBA-15 with pores of 4.4 or 8.0 nm, and MCM-41 with pores of 2.9 nm and polypropylene (PP) or functionalized PP containing hydroxyl groups (PPOH) were developed. The nanocomposite containing PPOH and SBA-15 with a pore of 8.0 nm showed higher toughness, stiffness, and transparency than the other nanocomposites.
Structure−property relationships of polypropylene-based nanocomposites obtained by dispersing mesoporous silica into hydroxyl-functionalized polypropylene. Part 2: Matrix−filler interactions and pore filling of mesoporous silica characterized by evolved gas analysis
Nanocomposites containing mesoporous silica (MPS) materials with various pore structures (SBA-15 and MCM-41 types) melt mixed into polypropylene (PP) or PP functionalized with hydroxyl groups (PPOH) were characterized by analytical pyrolysis techniques, such as evolved gas analysis (EGA)-mass spectrometry (MS) and heart-cut EGA-gas chromatography (GC)/MS, to evaluate the interactions between the polymer matrix and MPS and the pore filling of the MPS in the nanocomposite. The EGA-MS measurements revealed that nanocomposites with MPSs evolve specific degradation products, which can be attributed to strong interactions between the polymer molecules and the internal pores. The amount of these specific products increased upon increasing the pore size of the MPS and the hydroxyl content in the polymer matrix. Sufficiently large pores of MPS and high hydroxyl contents in the matrix appear to provide strong interactions because the MPS pores are well-filled with polymer molecules, which contributes to the improved physical properties of the nanocomposites.