Poly(2-hydroxyethyl methacrylate) (PHEMA) grafted polyethylene/polypropylene (PE/PP) nonwoven fabric by γ-initiation: Synthesis, characterization and benefits of RAFT mediation

Hybrid PET Track-Etched Membranes Grafted by Well-Defined Poly(2-(dimethylamino)ethyl methacrylate) Brushes and Loaded with Silver Nanoparticles for the Removal of As(III)

Nanoporous track-etched membranes (TeM) are promising materials as adsorbents to remove toxic pollutants, but control over the pore diameter and density in addition to precise functionalization of nanochannels is crucial for controlling the surface area and efficiency of TeMs. This study reported the synthesis of functionalized PET TeMs as high-capacity sorbents for the removal of trivalent arsenic, As(III), which is more mobile and about 60 times more toxic than As(V). Nanochannels of PET-TeMs were functionalized by UV-initiated reversible addition fragmentation chain transfer (RAFT)-mediated grafting of 2-(dimethyamino)ethyl methacrylate (DMAEMA), allowing precise control of the degree of grafting and graft lengths within the nanochannels. Ag NPs were then loaded onto PDMAEMA-g-PET to provide a hybrid sorbent for As(III) removal. The As(III) removal efficiency of Ag@PDMAEMA-g-PET, PDMAEMA-g-PET, and pristine PET TeM was compared by adsorption kinetics studies at various pH and sorption times. The adsorption of As(III) by Ag@DMAEMA-g-PET and DMAEMA-g-PET TeMs was found to follow the Freundlich mechanism and a pseudo-second-order kinetic model. After 10 h, As(III) removal efficiencies were 85.6% and 56% for Ag@PDMAEMA-g-PET and PDMAEMA-g-PET, respectively, while PET template had a very low arsenic sorption capacity of 17.5% at optimal pH of 4.0, indicating that both PDMAEMA grafting and Ag-NPs loading significantly increased the As(III) removal capacity of PET-TeMs.

Chelating Fabrics Prepared by an Organic Solvent-Free Process for Boron Removal from Water

A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, while the attachment reaction was carried out by immersing the grafted fabric in the NMDG aqueous solution. The chelating capacity of the chelating fabric prepared by reaction in the NMDG aqueous solution without any additives reached 1.74 mmol/g, which further increased to above 2.0 mmol/g when surfactant and acid catalyst were added in the solution. The boron chelation of the chelating fabric was evaluated in a batch mode. Fourier transform infrared spectrophotometer (FTIR) was used to characterize the fabrics. The chelating fabric can quickly chelate boron from water to form a boron ester, and a high boron chelating ability close to 18.3 mg/g was achieved in the concentrated boron solution. The chelated boron can be eluted completely by HCl solution. The regeneration and stability of the chelating fabric were tested by 10 cycles of the chelation-elution operations. Considering the organic solvent-free preparation process and the high boron chelating performance, the chelating fabric is promising for the boron removal from water.

A polymer hybrid film based on poly(vinyl cinnamate) and poly(2-hydroxy ethyl methacrylate) for controlled flurbiprofen release

A crosslinked polymer hybrid film, ipn-poly(vinyl cinnamate-graft-2-hydroxy ethyl methacrylate)-v-poly(ethylene glycol dimethacrylate) was synthesized by UV initiation using poly(vinyl cinnamate) (polyVCi), 2-hydroxy ethyl methacrylate (HEMA) monomer and ethylene glycol dimethacrylate (EGDMA) crosslinker. Benzophenone (Ph₂CO), was used as the photoinitiator. The synthesis was optimized by changing the concentration of HEMA, Ph₂CO, EGDMA, and UV irradiation time. PolyVCi undergoes photocrosslinking by 2 + 2 photocylo addition while the monomer/crosslinker couple, HEMA/EGDMA, undergoes free radical polymerization and crosslinking to form EGDMA crosslinked polyHEMA. Hence, simultaneous interpenetrating polymer network (IPN) formation occurs. The IPN consists of dual network of photocrosslinked polyVCi and EGDMA crosslinked polyHEMA chains. Grafting of HEMA/EGDMA chains on the polyVCi backbone also occur during network formation. The chemical functionalities present in the polyVCi/polyHEMA/polyEGDMA IPN films obtained were characterized by FTIR and SEM analysis. The contact angle measurements show enhanced wettability of the IPN film compared to polyVCi surface. TGA analysis confirms thermal stability of the films. Swelling behavior of the films examined in water and in ethanol reveals the effects of the chemical natures of polyVCi and polyHEMA as well as that of crosslinking on the hydrophilicity of the film. The films were tested as drug release matrices using flurbiprofen. The drug was loaded into the film matrix during IPN formation under UV irradiation. PolyVCi/polyHEMA/polyEGDMA IPN proved to be a suitable release matrix for flurbiprofen demonstrating controlled release behavior and zero-order release kinetics. The release mechanism was confirmed by its Ritger-Peppas “n” value (1.00 to 1.42), which indicates super case II release.

PHEMA Hydrogels Obtained by Infrared Radiation for Cartilage Tissue Engineering

Although the exposure of polymeric materials to radiation is a well-established process, little is known about the relationship between structure and property and the biological behavior of biomaterials obtained by thermal phenomena at 1070 nm wavelength. This study includes results concerning the use of a novel infrared radiation source (ytterbium laser fiber) for the synthesis of poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel in order to produce medical devices. The materials were obtained by means of free radical polymerization mechanism and evaluated regarding its cross-linking degree, polymer chain mobility, thermal, and mechanical properties. Their potential use as a biomaterial toward cartilage tissue was investigated through incubation with chondrocytes cells culture by dimethylmethylene blue (DMMB) dye and DNA quantification. Differential scanning calorimetry (DSC) results showed that glass transition temperature (Tg) was in the range 103°C–119°C, the maximum degree of swelling was 70.8%, and indentation fluency test presented a strain of 56%–85%. A significant increase of glycosaminoglycans (GAGs) concentration and DNA content in cells cultured with 40 wt% 2-hydroxyethyl methacrylate was observed. Our results showed the suitability of infrared laser fiber in the free radicals formation and in the rapid polymer chain growth, and further cross-linking. The porous material obtained showed improvements concerning cartilage tissue regeneration.

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ever increasing set of computational and simulation tools that allow understanding and predictions of these surface-grafted polymer architectures. The aim of this contribution is to provide a comprehensive review that critically assesses recent advances in the field and highlights the opportunities and challenges for future work.

Towards new proton exchange membrane materials with enhanced performance via RAFT polymerization

This study focuses on the synthesis of well-defined proton exchange membranes (PEM) for fuel cell applications using reversible addition–fragmentation chain transfer (RAFT) polymerization in the radiation-induced grafting part of the overall process.