Biosafety evaluation and quantitative determination of poly(hexamethylene biguanide) (PHMB) coated on cellulosic fabrics by Kubelka–Munk equation

Abstract

It is a challenge to determine the quantity of cationic finishing agents on the surface of cellulosic fabrics. Herein, we report a direct and feasible method by Kubelka-Munk equation to quantify the cationic poly (hexamethylene biguanide) hydrochloride (PHMB) adsorbed onto cotton fabrics based on the principle of formation of a stable blue dye between PHMB and bromophenol blue sodium (BPB). The adsorption of PHMB onto cotton fabrics was first investigated and the maximum adsorption of PHMB was found to be around 8 mg per gram of cotton fabric. After being dyed with BPB, colour strength shows a positive correlation with PHMB at low concentrations (<2400 mg/L). A linear relationship with a high correlation (C(PHMB) = (K/S-0.7411)/3.4517, R 2 =0.9983) was thus established between colour strength and PHMB concentration. However, this equation should fulfill four requirements for quantifying PHMB: (1) the distribution of PHMB on the surface of cellulosic fabric should be in the form of a monolayer with the content less than 5.3 mg/g; (2) an excess of BPB dyebath should be applied; (3) the dyeing should come to equilibrium; and (4) the fabrics should be evenly dyed. Moreover, MTT assay results indicate that excess PHMB coated on cotton fabrics can cause cytotoxicity and the quantity of PHMB should not exceed 4.62 mg per gram of cotton fabrics for the purpose of biosafety. The sample can be considered noncytotoxic if the K/S value is lower than 13.2 after dyeing with BPB.

Poly(hexamethylene biguanide) hydrochloride (PHMB)-based materials: synthesis, modification, properties, determination, and application

“…71,72 The maximum concentration of PHMB allowed in the swimming pool is 0.001% (w/v), while for textiles the allowed content is up to 0.4% o.w.f. 73,74…”

“…235 nm). 73 However, the disadvantage of this method is equally notable. It only applies to PHMB aqueous solutions, with limited accuracy.…”

“…Wang et al reported a promising method for directly quantifying PHMB on cotton fabrics according to the Kubelka–Munk equation. 73 Analogously, the principle was based on the stoichiometric reaction between PHMB and bromophenol blue with the formation of colored stable complexes. The color strength was shown to be in a linear relationship with PHMB within limits.…”

Fabrication and characterization of polyurethane and zirconium carbide coated cotton yarn

“…Relative color strengths (K/S values) and the L, a*, b*, h*, C* values of the cotton/PU/ZrC fabric before and after washing were measured on a spectrophotometer (CS-820, Hangzhou Caipu Technology Co., Ltd, China) with illuminant D65 and 10°observer. K/S values have been determined using the Kubelk and Munk equations (Wang et al 2021). L* represents the brightness (100 = white, 0 = black), a* represents the red/green coordinate (positive sign = red, negative sign = green), and b* represents the yellow/blue coordinate (positive sign = yellow, negative sign = blue).…”

Antiviral and Antibacterial 3D-Printed Products Functionalised with Poly(hexamethylene biguanide)

“…In this study, poly(hexamethylene biguanide) (PHMB), a polymer that bears the positively charged biguanide in the repeating unit of the polymer chain (see Figure 1), was mixed in photosensitive resins to print the antimicrobial samples and products by digital light processing (DLP) technique. PHMB is a mature synthetic antimicrobial agent applied in various industries for over 60 years [30][31][32][33]. Its non-leaching property is attributed to its high molecular weight, approximately 1600 to 2600 g/mol; hence there are many advantages of its applications, such as improved environmental stability, low toxicity, high biocompatibility and satisfactory retention of antimicrobial activity [34][35][36][37][38].…”