Development and Optimization of UV-Induced Chemical Foaming Process

Abstract

In this study, we have investigated a UV-induced chemical foaming method to create a nanocellular polymer thin film. A small amount of photoacid generator (PAG) was mixed with poly(methyl methacrylate-co-tert-butyl acrylate) (PMMA-co-PtBA). After UV irradiation followed by heating, tert-butyl ester group in the PtBA was deprotected with the acid generated from the PAG, and isobutene gas was produced in the polymer matrix. The resulting polymer foamed with the gas had cell size and cell density ranging from 100 to 200 nm and from 1 × 10 13 to 9 × 10 13 cells/cm 3 , respectively. Several key parameters were found that would affect largely on the formation of the nanocellular structure, i.e., foaming time and temperature, UV dose, molecular weight of polymer.

Self-foaming polymers: Opportunities for the next generation of personal protective equipment

“…[169] The use of UV activation enabled to access to patterning of the material at the nanoscale (Figure 13). [168,170,171] Such nanoporous materials are reported to find applications in high-performance thermal insulation [172] or filtration [173] materials. They might also be attractive alternatives to nanoporous materials used as COVID19 protective masks that were prepared by a multi-step process consisting of using inorganic templates prior polymer material etching.…”

“…Figure 26: The typical range of foam density and glass transition temperature (Tg) obtained by using self-foaming method presented in the review (when provided). [56][57][58][59]74,75,98,100,105,106,123,126,137,[144][145][146][147][148]158,160,167,170,171,187,190,195,212,214,223,[227][228][229]233,237,[242][243][244]248,251,255] In the context of toxicity concerns related to the use of isocyanates, the other self-foaming techniques described in this review are offering promising alternatives to develop safer and environmentally benign foaming technologies, notably for the sector of PPE. Their transfer to the industry is probably just a question of time and more importantly, cost.…”

Effect of blowing agent concentration of ultra‐low density NBR/PVC composite foams on compressive behavior and energy‐absorption characteristics

“…[12,13] These properties have been exploited for widespread applications in several industries, including building and construction, automobile, marine, medicine, and sports. [14][15][16] Polymer-based foams are usually fabricated using three types of foaming methods: physical, [17,18] chemical, [19] and mechanical. [20] Chemical foaming is the most commonly used method.…”

Control of the Cell Structure of UV-Induced Chemically Blown Nanocellular Foams by Self-Assembled Block Copolymer Morphology

“…In the case of a random copolymer, poly(methyl methacrylate-r-tert-butyl acrylate) (PMMA-r-PtBA), nanocellular foams generated from UV-induced chemical foaming have cell sizes of 100−200 nm. 41 To enhance the cell ordering, we incorporated UV-induced chemical foaming with self-assembly of the block copolymer. 42 As shown in Scheme 1b, this process involves two major steps:…”