Photopolymerization of Zeolite/Polymer-Based Composites: toward 3D and 4D Printing Applications

Abstract

In recent years, photopolymerization has found wide applications in industry and daily life, especially 3D printing. However, some defective properties of photopolymers limit their development, such as their mechanical properties, density, compressive strength, and functionality. Herein, in this work, we reported the fabrication of composites containing seven different kinds of zeolites used as fillers under mild photopolymerization conditions (LTA-5A was selected as the benchmark zeolite), that is, visible LED light irradiation at room temperature under air. The filler properties affecting the related depth of cure and the enhanced mechanical (the storage modulus increased by 10-fold compared to that of a pure polymer) and functional properties were examined in detail. In addition, the production of 3D patterns was performed through direct laser writing (DLW) as a lithography technique. As a real breakthrough, the 3D printing of zeolite/polymer composites is presented here for the first time with high filler contents (up to 75 wt %) using this stereolithography approach. 4D behavior can be established in the presence of water, that is, the 3D object can change the shape and return to the starting geometry after desiccation. Remarkably, after debinding of the composites by thermal treatment, a high zeolite porosity can be regenerated. Therefore, the 3D printing of zeolites is possible in two steps: (i) photopolymerization of organic/zeolite composites to generate the desired shape, followed by (ii) removal of the organic part by thermal treatment. This work is expected to lead to valuable developments in the field of photopolymerization reactions in highly filled composites (with the filler content exceeding 50 wt %) and thereby expand their potential application for 3D or 4D printing in the fields of, for example, high-performance lightweight materials and adsorption.

Recent Advances in bis-Chalcone-Based Photoinitiators of Polymerization: From Mechanistic Investigations to Applications

“…Indeed, hydration and dehydration of the hydrophilic PEG polymer can be advantageously used for shape modification. More precisely, 4D printing consists of elaborating an object of precise thickness and shape that can be modified subsequent to the polymerization process by means of an external stimulus such as heat [225][226][227][228], light [229], water [230][231][232], or other stimuli. Thus, after printing a cross with a high spatial resolution via 3D printing using the three-component chalcone/Iod/EDB (1.5%/1.5%/1.5%, w/w/w) photoinitiating systems based on chalcones C60 and C64, swelling and thermally induced dehydration resulted in significant modification of the shapes of the crosses.…”

Photopolymerization of Zeolite Filler‐Based Composites for Potential 3D Printing Application and Gas Adsorption Applications

“…In our previous work, we successfully obtained the composite with zeolite content up to 75 wt%. [40] It is a challenge to manufacture the composite with higher zeolite content, because the depth of cure (DOC) is normally determined by the optical properties of filler and monomer during the photopolymerization process. [43,44] Due to the presence of fillers with different geometries and refractive indices, the light transmittance of filled formulations can be affected by the light absorption, the increasing and/or change in light scattering, and the refractive index mismatch between the polymer and the filler.…”

“…[34][35][36] In recent years, more and more researchers are working to combine zeolite as fillers with polymers to produce composites or hydrogel composites applied in medicine industry, [37,38] adsorption and separation industry. [39,40] Zhang et. al.…”

“…In our previous work, we mainly studied the photopolymerization of zeolite/polymer composite (the photopolymerization kinetics and the depth of cure for composites), [42] the mechanical and functional properties of composites (zeolite maximum content ~75 wt%). [40] In this work, the proof-concept study describes fabrication of zeolite-polymer composite with very high filler content (80-95 wt%) through photopolymerization, and the corresponding 3D-printed objects can also be obtained. Moreover, after debinding/sintering at the appropriate temperature, the material retains the zeolite porosity.…”

Nitro‐Carbazole Based Oxime Esters as Dual Photo/Thermal Initiators for 3D Printing and Composite Preparation

“…[ 1,2 ] This polymerization technique has been successfully applied in many fields including conventional industries (e.g., ink, adhesive) and many cutting‐edge technologies (e.g., 3D–4D printing, microelectronic processing, etc.). [ 3–7 ] Light‐emitting diodes (LEDs) demonstrate many distinct advantages over traditional UV irradiation sources such as security, low cost and longer emission wavelengths. In recent years, near‐UV and visible LEDs have been widely used in scientific research and industrial production.…”