A novel nanosilica/graphene oxide hybrid was prepared, which can simultaneously improve the typical properties (dielectric, thermal conductivity, thermal stability, and mechanical properties) and flame retardancy of epoxy resin.

The current printing mechanism of the bottom-up vat photopolymerization 3D printing technique places a high demand on the fluidity of the UV-curable resin. Viscous high-performance acrylate oligomers are compounded with reactive diluents accordingly to prepare 3D printable UV-curable resins (up to 5000 cps of viscosity), yet original mechanical properties of the oligomers are sacrificed. In this work, an elaborated designed linear scan-based vat photopolymerization system is developed, allowing the adoption of printable UV-curable resins with high viscosity (> 600,000 cps). Briefly, this is realized by the employment of four rollers to create an isolated printing area on the resin tank, which enables the simultaneous curing of the resin and the detachment of cured part from the resin tank. To verify the applicability of this strategy, oligomer dominated UV-curable resin with great mechanical properties, but high viscosity is prepared and applied to the developed system. It is inspiring to find that high stress and strain elastomers and toughened materials could be facilely obtained. This developed vat photopolymerization system is expected to unblock the bottleneck of 3D printed material properties, and to build a better platform for researchers to prepare various materials with diversiform properties developed with 3D printing.

Silver (Ag) ornamented TiO₂ semiconducting nanoparticles were synthesized through the sol-gel process to be utilized as nanofillers with photo resin to enhance the mechanical and thermal properties of stereolithography 3D printed objects. The as-prepared Ag-TiO₂ nanoparticles (Ag-TNP) were typified and qualified by XRD, XPS, Raman, and FESEM; TEM analysis dissected the morphologies. The enhancement in the tensile and flexural strengths of SLR/Ag-TNP nanocomposites was noted as 60.8% and 71.8%, respectively, at the loading content of 1.0% w/w Ag-TNP within the SLR (stereolithography resin) matrix. Similarly, the thermal conductivity and thermal stability were observed as higher for SLR/Ag-TNP nanocomposites, equated to neat SLR. The nanoindentation investigation shows an excerpt hike in reduced modulus and hardness by the inclusion of Ag-TNP. The resulted thermal analysis discloses that the introduction of Ag-TNP can appreciably augment the glass transition temperature (T_g), and residual char yield of SLR nanocomposites remarkably. Hence, the significant incorporation of as-prepared Ag-TNP can act as effective nanofillers to enhance the thermal and mechanical properties of photo resin.

Fabrication of low-cost, durable and efficient metal oxide nanocomposites were successfully synthesized and reinforced with photo-resin via 3-dimensional printing. Here, we put forward a novel approach to enhance the mechanical and thermal behaviors of stereolithography (SLA) 3D printed architecture by adding TiO₂ nanoparticles (TNPs) in different crystalline phases (anatase and rutile), which were obtained at different annealing temperatures from 400 °C to 1000°C. The heat-treated anatase TNPs were scrutinized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, diffusive reflectance spectroscopy (DRS), and transmission electron microscopy (TEM) analysis. Among all the samples, at 800 °C, annealed anatase TNPs exposed a highly crystalline anatase phase, having a low energy bandgap and a comparably high tensile strength (47.43 MPa) and high elastic modulus (2.261 GPa) for the 3D printed samples, showing improvement by 103% and 32%, respectively, compared with the printed pristine stereolithography resin (SLR) sample. Moreover, enhanced storage modulus and tan δ values were achieved via the better interfacial interactions between the incorporated nanofillers and the SLR matrix. In addition to this, enhanced thermal conductivity and thermal stability of the SLR matrix were also noted. The low energy bandgap and nanoscale size of the fillers helped to achieve good dispersion and allowed the UV light to penetrate at a maximum depth through the photo resin.

The development of degradable plastic foams is in line with the current development concept of being pollution free and sustainable. Poly(lactic acid) (PLA) microporous foam with biodegradability, good heat resistance, biocompatibility, and mechanical properties can be successfully applied in cushioning packaging, heat insulation, noise reduction, filtration and adsorption, tissue engineering, and other fields. This paper summarizes and critically evaluates the latest research on preparing PLA microporous materials by supercritical carbon dioxide (scCO₂) physical foaming since 2020. This paper first introduces the scCO₂ foaming technologies for PLA and its composite foams, discusses the CO₂-assisted foaming processes, and analyzes the effects of process parameters on PLA foaming. After that, the paper reviews the effects of modification methods such as chemical modification, filler filling, and mixing on the rheological and crystallization behaviors of PLA and provides an in-depth analysis of the mechanism of PLA foaming behavior to provide theoretical guidance for future research on PLA foaming. Lastly, the development and applications of PLA microporous materials based on scCO₂ foaming technologies are prospected.