Improved Dimensional Stability and Mold Resistance of Bamboo via In Situ Growth of Poly(Hydroxyethyl Methacrylate-N-Isopropyl Acrylamide)

Abstract

Bamboo is a natural and renewable building material but its application has been limited due to the low dimensional stability and poor durability against mold. In this study, monomers of hydroxyethyl methacrylate (HEMA) and N-isopropyl acrylamide (NIPAM) were impregnated in bamboo to facilitate the in situ growth of poly-HEMA and NIPAM (PHN) copolymer. Prior to that, the effects of different reaction conditions, including the molar ratio of HEMA to NIPAM and their concentrations, the amount of initiator (ammonium persulfate, APS) and crosslinking agents (N,N′-Methylenebisacrylamide (MBA), and glutaric dialdehyde (GA)) on the swelling capacity of PHN were optimized. The formation of PHN was confirmed by using Fourier transform infrared spectroscopy and thermogravimetric analysis, which shows the characteristics peaks of both HEMA and NIPAM, and increased pyrolysis and glass transition temperatures, respectively. After impregnation of PHN pre-polymerization formulation to bamboo, it was observed that PHN filled most of the pits in the bamboo cell wall and formed a tight network. Moreover, the dimensional stability of PHN treated bamboo was significantly improved with an anti-swelling efficiency of 49.4% and 41.7%, respectively, after wetting–drying and soaking–drying cycles. A mold infection rate of 13.5% was observed in PHN-treated bamboo as compared to a 100% infected control group after a 30-day mold resistance test. Combined results indicate that in situ polymerization of HEMA and NIPAM in bamboo is a promising method to develop exterior used bamboo products with enhanced dimensional stability and mold resistance.

Copolymer Involving 2-Hydroxyethyl Methacrylate and 2-Chloroquinyl Methacrylate: Synthesis, Characterization and In Vitro 2-Hydroxychloroquine Delivery Application

“…For CQMA-co-HEMA, Figure 8 shows a comparison between the thermograms of the PHEMA homopolymer and those of the copolymers involving CQMA and HEMA monomers with different compositions. As shown in these profiles, PHEMA presented a glass transition temperature, T g , at 95 • C, which agreed with that of the literature [30], while the thermal curves of the copolymer showed a shift in the T g towards low temperatures, which increased with the CQMA content. This appeared to be evident due to the effect of the steric hindrance of the chloroquinyl methacrylyl substituent of the CQMA units.…”

In Situ Construction of Thermotropic Shape Memory Polymer in Wood for Enhancing Its Dimensional Stability

“…In comparison with the untreated wood, the modified wood displayed swelled cell walls, densely packed with few spaces between the cells. For the treated samples, most of the pits in the vessel were also stuffed with white polymer, which suggested that a large amount of modifier solution penetrated the wood via the vessels and further went through the pits to the adjacent cells [37,50]. As the modifier solution entered the cell wall and polymerized, the cells would bulk and swell, which was confirmed by the VPG of the treated wood.…”

“…In the M-D test, the volumes (V 0 ) and weight (M 0 ) of the samples dried following the procedure mentioned above were firstly determined, then the samples were conditioned in an incubator set at a relative humidity of 85 ± 5% and temperature of 25 ± 2 • C for 3 days, followed by another measurement of the volume (V t ) and weight (M t ). These drying and moistening procedures were repeated to obtain three cycles of variations in the weight and volume [37]. The S-D cycles for the blocks were similar to the M-D cycles, except for replacing the moistening procedure with water immersion.…”

Preparation of uniformly dispersed N-isopropylacryl-amide/acrylic acid/nanosilver composite hydrogel and its anti-mold properties

“…As a new renewable resource with a short growth cycle and a high economic value, bamboo has been widely used in interior decoration, architecture, automobile manufacturing, and other fields (Chung and Yu 2002;Sharma et al 2015;Yuan et al 2017;Liu et al 2019;Wu et al 2019;Liu et al 2020). However, bamboo is vulnerable to mold invasion, and the resulting loss accounts for approximately 10% of the total bamboo output (Zhang et al 2020).…”