Article pubs.acs.org/IECR
Microwave-Assisted Glycolysis for PET with Highly Hydrophilic Surface Jae Yeoun Cho, Cheol-Jae Hong, and Hyung-Min Choi* Department of Organic Materials and Fiber Engineering, Soongsil University, Seoul, Republic of Korea 156-743 S Supporting Information *
ABSTRACT: PET fabric with highly hydrophilic surface was obtained by microwave-assisted, nonaqueous glycolysis under alkali condition. Surface hydrophilicity was measured by water drop test, vertical wicking test, and contact angle measurement. At 120 s of irradiation, the glycolyzed PET showed instantaneous wetting with a low level of alkali concentration, such as 0.1% NaOH. DSC and SEM analyses were used to investigate thermal and topological characteristics of the glycolyzed PET. Depending on the required hydrophilicity, the level of alkali and irradiation time must be adjusted. Use of microwave-assisted modification could reduce the treatment time to less than 180 s from 1 to 2 h in a conventional dyeing machine treatment, allowing considerable savings in energy and processing costs.
1. INTRODUCTION Poly(ethylene terephthalate) (PET) is one of the most important materials in both apparel and nonfibrous end uses due to its excellent strength, chemical resistance, clarity, processability, and dimensional stability.1 However, the very low hydrophilicity of PET results in discomfort, a high propensity toward pilling, and electrostatic charge during wearing.1−8 Various methods were examined to enhance the hydrophilicity of PET including hydrolysis by strong acid or alkali,2,3 amine treatment,3 alcoholysis,8 and treatment by various radiations (plasma).9,10 These methods, however, produce some problems, such as generation of undesired ionic groups, yellowing effect, considerable strength loss, and substantial initial capital investment.4,8−10 Therefore, a new, better process has yet to be developed to make PET more hydrophilic. Nonaqueous glycolysis of PET has been extensively examined for recycling of PET wastes to form its monomers.1,2,4 Alkali catalysts such as sodium hydroxide and sodium carbonate were used in decomposition of PET with glycolysis.1,4 Use of these alkali catalysts is preferred over heavy metal catalysts because of environmental concerns and economic reasons. Therefore, our previous research showed that the controlled decomposition of PET at low temperature (
