Mechanically strong polystyrene nanocomposites by peroxide-induced grafting of styrene monomers within nanoporous cellulose gels

Thermoformable and transparent one-component nanocomposites based on surface grafted cellulose nanofiber

One-component nanocomposites based on poly(methyl methacrylate)(PMMA) and polystyrene (PS) grafted cellulose nanofiber (CNF) with high polymer graft percentage were fabricated. At relative ambient conditions, less active vinyl monomer, MMA, and styrene were grafted from CNF via surface-initiated Cu(0)-mediated reversible deactivation radical polymerizations (RDRP), and PMMA/PS grafted CNFs could reach a graft percentage as high as 7550 % and 3530 %, respectively. The one-component composite films were manufactured by simple hot-pressing subsequentially. Optical transparency, thermal stability, and glass transition temperature of one-component nanocomposites were enhanced dramatically in contrast with the bicomponent nanocomposite. The uniform fracture surface confirmed the uniform dispersity by morphological observation. Mechanical tests indicated that break elongation and tensile strength ascended notably, and tensile modulus slightly descended as the graft percentage increased for PS and PMMA grafted CNF one-component composite. It was concluded that for glassy graft chains, obtaining one-component nanocomposites with high enough graft chain length was essential to achieve moderated mechanical performance without compromising optical properties and thermal manufacturing ability.

Green and sustainable cellulose-based shape memory composites with excellent conductivity for temperature warning

Green and sustainable cellulose-based composites containing poly(ε-caprolactone) (PCL) with temperature-induced shape memory properties and conductivity performance are presented. The composites are fabricated by in situ polymerization of ε-caprolactone (ε-CL) monomer in three-dimensional porous cellulose gels, and then silver-porous cellulose gel/poly(ε-caprolactone) (Ag-Cell/PCL) composites are fabricated by depositing Ag onto the surface of porous cellulose gel/poly(ε-caprolactone) (Cell/PCL) composites. The addition of PCL not only improves the mechanical properties of the Cell/PCL composites but also endows them with excellent shape memory properties. The Cell/PCL composites exhibit a high shape-fixing rate (98.9%) and can recover to their original shape within 8 s without external force. In addition, the Ag-Cell/PCL composites show superior and stable conductivity under different bending angles. Finally, a temperature warning sensor with fast performance is successfully designed using Ag-Cell/PCL composites. This work provides a means to develop temperature warning systems based on shape memory polymers.

Preparation of a Novel Cellulose-Styrene Copolymer Adsorbent and Its Adsorption of Nitrobenzene from Aqueous Solutions

A novel cellulose–styrene copolymer adsorbent (cellulose-St) was prepared using free radical polymerization. Successful polymerization was confirmed through Fourier Transform Infrared Spectroscopy (FTIR), Carbon 13 Solid Nuclear Magnetic Resonance (¹³C NMR) Spectroscopy, Scanning Electron Microscopy (SEM), etc. Cellulose-St possessed good hydrophobicity, and the best water contact angle of cellulose-St samples could reach 146°. It had the ability of adsorption for nitrobenzene (NB), and the adsorption process could be well described by the pseudo-second-order (R² > 0.99) and three-stage intraparticle diffusion (R² > 0.99) kinetic models. Furthermore, the dynamic adsorption experiments revealed that cellulose-St had the potential for continuous separation of NB in water, and the breakthrough point for the initial NB concentration of 10 mg/L reached 1.275 L/g. Moreover, cellulose-St exhibited excellent environmental adaptability that it could maintain its hydrophobicity and adsorption ability for NB in strong acids, strong alkalis, or organic solvents. The used cellulose-St could be reused after washing with ethanol and keep almost constant adsorption capacity after ten cycles.

Filament Extrusion and Its 3D Printing of Poly(Lactic Acid)/Poly(Styrene-co-Methyl Methacrylate) Blends

Herein, we report the melt blending of amorphous poly(lactide acid) (PLA) with poly(styrene-co-methyl methacrylate) (poly(S-co-MMA)). The PLAx/poly(S-co-MMA)y blends were made using amorphous PLA compositions from 50, 75, and 90wt.%, namely PLA50/poly(S-co-MMA)50, PLA75/poly(S-co-MMA)25, and PLA90/poly(S-co-MMA)10, respectively. The PLAx/poly(S-co-MMA)y blend pellets were extruded into filaments through a prototype extruder at 195 °C. The 3D printing was done via fused deposition modeling (FDM) at the same temperature and a 40 mm/s feed rate. Furthermore, thermogravimetric curves of the PLAx/poly(S-co-MMA)y blends showed slight thermal decomposition with less than 0.2% mass loss during filament extrusion and 3D printing. However, the thermal decomposition of the blends is lower when compared to amorphous PLA and poly(S-co-MMA). On the contrary, the PLAx/poly(S-co-MMA)y blend has a higher Young’s modulus (E) than amorphous PLA, and is closer to poly(S-co-MMA), in particular, PLA90/poly(S-co-MMA)10. The PLAx/poly(S-co-MMA)y blends proved improved properties concerning amorphous PLA through mechanical and rheological characterization.