X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide.

Worawat Poltabtim,Kiadtisak Saenboonruang,Narongrit Sombatsompop,Vichai Rosarpitak,Ekachai Wimolmala,Teerasak Markpin

doi:10.3390/polym13132212

Worawat Poltabtim, Kiadtisak Saenboonruang + Show 4 more

Open Access

https://doi.org/10.3390/polym13132212

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Abstract

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

Highlights

X-rays are ionizing radiation with energies of 100 eV–100 keV and frequencies of 1016–1020 Hz and are currently utilized in various applications, including X-ray imaging for the diagnosis of brain and lung cancers [1], low-dose X-ray radiotherapy [2], X-ray fluorescence (XRF) and X-ray diffraction (XRD) for material and archeological characterizations [3,4,5], and X-ray irradiation of economic plants to accelerate breeding and mutations [6]
The results suggested that the values of the Izod impact strength and hardness (Shore D) were enhanced with the addition of Bi2O3, except for the wood/polyvinyl chloride (WPVC) composites containing 100 pph Bi2O3 and 40 pph wood particles that had noticeably lower Izod impact strength than those with 75 pph Bi2O3 and 40 pph wood particles
The results suggested that an increased Bi2O3 content led to non-statistically differences in flexural strength, increased X-ray attenuation, Izod impact strength, hardness (Shore D), and density, but decreased water absorption

Summary

Introduction

X-rays are ionizing radiation with energies of 100 eV–100 keV and frequencies of 1016–1020 Hz and are currently utilized in various applications, including X-ray imaging for the diagnosis of brain and lung cancers [1], low-dose X-ray radiotherapy [2], X-ray fluorescence (XRF) and X-ray diffraction (XRD) for material and archeological characterizations [3,4,5], and X-ray irradiation of economic plants to accelerate breeding and mutations [6]. In particular for X-ray shielding materials used as movable panels, radio-diagnostic walls, and transportation casks, wood/plastic composites (WPC), especially wood/PVC (WPVC) composites, are most interesting for such purposes due to their light weight, low water absorption, termite resistance, humidity resistance, environmental erosion resistance, dimensional stability, and low maintenance requirements, resulting in their broad potential for utilization [28,29,30,31] Despite their attractive properties, the use of WPC as radiation shielding material, especially for X-ray attenuation, is presently limited as most of available products and reports have been primarily aimed at preventing the interference of low-energy electromagnetic (EM) waves (radio and microwaves) on electrical devices.

Preparation of WPVC Composites

Materials and Chemicals

Water Absorption Measurement

Mechanical Properties

Conclusions