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An after-glow capacitively coupled discharge technique has been used to fabricate ultra-thin proton exchange composite membranes in a plasma polymerization reactor, where styrene and acrylic acid are used as starting materials. By this technique, a good preservation of monomer structure can be achieved. The structure and composition of the plasma polymerized membranes were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The morphology information and thickness of the membranes were provided by Scanning electron micrographs (SEM). The synthesized membranes are dense with uniform structure and rich with carboxyl acid groups. This novel plasma polymerization technique is expected to be used for the preparation of alternative membranes to preserve their monomer structure to a maximum extent.

Divinylbenzene-80 (DVB-80) and polar monomer acrylic acid (AA) having hydrogen bonding at a total monomer loading of 5 vol% were precipitated-copolymerized in a variety of organic solvents with 2,2′-azobis(isobutyronitrile) (AIBN) as initiator. The experiments were investigated from a two-dimensional matrix, i.e., the actual crosslinking degree of DVB varying from 0 to 80% and the solvent composition varying from 0 to 100% of toluene mixture with acetonitrile, when the mixture of acetonitrile and toluene was used as the reaction solvent. Under various reaction conditions, six distinct morphologies including soluble polymers, swellable microgels, coagulum, irregular microparticles, and nano-/micrometer microspheres were formed and the structures of these polymer architectures were described. A morphological map was utilized to discuss the effects of both crosslinking degree of DVB and composition of solvent on the transitions between morphology domains. The results demonstrated that the microspheres are formed by an internal contraction due to the marginal solvency of the continuous phase and the crosslinking of the polymer network through the covalent bonding from DVB as well as the interchain hydrogen-bonding between the carboxylic acid units.

Macroporous acrylonitrile-acrylic acid (AN-AA) copolymer hydrogels were synthesized by free-radical solution polymerizations, using ammonium persulfate (APS)/N,N,N′,N′-tetramethylethylenediamine (TEMED) redox initiator system and alcohols porogens. The morphology, temperature and pH sensitive swelling behavior, and swelling kinetics of the resulting hydrogels were investigated. It was found that alcohol type and concentration had great influences on the pore structure and porosity of hydrogels. The pore size of hydrogel increases with the moderate increase of the length of alcohol alkyl chain. However, a further increase of alkyl length would result in the formation of cauliflower-like structure and the decrease of pore size. The porosity of hydrogels increases with the increase of porogen concentration in the polymerization medium. The hydrogels with macroporous structure swell or shrink much faster in response to the change of pH in comparison with the conventional hydrogel without macroporous structure. Furthermore, the response rate is closely related to the porosity of the hydrogels, which could be easily controlled by modulating the concentration of the porogen in the medium. The circular swelling behavior of hydrogels indicated the formation of a relaxing three-dimensional network.

Monodisperse poly(poly(ethyleneglycol) methyl ether acrylate-co-acrylic acid) (poly(PEGMA-co-AA)) microspheres were prepared by distillation-precipitation polymerization with divinylbenzene (DVB) as crosslinker with 2,2′-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%. The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.

The optical properties of CdSe quantum dots (QDs) capped by thioglycolic acid (TGA) before and after surface modification with poly (acrylic acid) grafted onto salep (salep-g-PAA), as a biopolymer-based multidentate ligand, were examined. The results showed that the fluorescence intensity as well as the stability of CdSe QDs was incredibly increased after surface modification with the biopolymer-based ligand. To provide more evidence for the occurrence of surface modification, the prepared CdSe–salep-g-PAA QDs were characterized by thermo-gravimetric analysis (TG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).

In this study, we synthesized semi-crystalline thermosetting polymer that have two-way-reversible shape memory effect (2W-SME) with a single crystalline phase and an amorphous phase. The polymer could be synthesized readily and its glass transition temperature (Tg) could be tuned over a wide range. The effect of acrylic monomers on the degree of cross-linking, the effects of different conditions, the applied stress, the acrylic monomers used, and the phase ratio of the crystalline and amorphous domains on the 2W-SME were studied. Measurement results confirmed that the polymer showed the 2W-SME and, the strongest 2W-SME achieved under the optimized conditions corresponded to a reversible deformation of 8.5%.

In this study, humidity-sensitive polymer layer containing phenol-formaldehyde resin prepared by spinning coating on the comb-shape type electrode followed by UV-graft polymerization of soluble monomer was performed to improve the sensitivity. In this investigation, grafting of P-styrenesulfonic acid sodium salt (NaSS) treated with hexamethyldisilazan (HMDSZ) plasma and acrylic acid (AAc) followed by isopropanol (IPA) plasma were used as monomer for UV surface graft polymerization. Results show the first one adding different ratio of phenol-formaldehyde resin. This type of sensor has linear response with %RH, and high sensitivity (impedance from 10⁶ to 10³). The impedance of second type of sensor was linear response with %RH, impedance varies from 10⁷ to 10⁵.

Today, fossil carbon provides us with fuels (energy), polymers (packaging, insulating and building materials, household utensils, glues, coatings, textiles, 3D-printing inks, furnitures, vehicle parts, toys, electronic and medical devices, etc.) and biologically active substances (drugs (Chapter 9), flavorings, fragrances, food additives, plant protection products, etc.). In this chapter we discover the modern materials of our civilization which are very often polymers derived from oil. They are referred to as “plastics” (annual world production: 380 × 10⁶ tons). Their production consumes 8% of the crude oil extracted (ca. 5 billion tons per year). An increasing part of the plastics originates from renewable resources (less than 10% today, see Section 11.10, bio-sourced plastics). Plastics make life easy for us, but at the underestimated cost of damage to our environment (Figure 8.1) and our health. They contaminate the hydrosphere and the agricultural soil. The atmosphere is also contaminated by microplastics…