College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
National Engineering Laboratory for Modern Silk, Suzhou 215123, China
Monomer of polyamide (PA66) and flame-retardant intermediate product (FR) were firstly synthesized, and the flame-retardant (PA-FR) was further gained by polymerization of PA66 and FR. The structure of PA-FR was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The thermal properties of PA-FR and the finished fabric were evaluated by thermal gravity analysis (TGA) and differential scanning calorimetry (DSC). Moreover, X-ray diffraction analysis (XRD) showed that melting eutectic reaction occurred between PA-FR and nylon fabric. The experimental results showed that the limiting oxygen index (LOI) value of PA-FR treated fabric and PA-FR treated fabric after 10 laundries were improved to 28.8% and 26.4%, respectively. It implied that PA-FR had a good and durable function of imparting fire-resistance to nylon fabric.
Keywords: nylon fabric, flame-retardant, synthesis, flame-retardant finishing, eutectic
Nylon is one of the polymers most used for synthetic fibers.1 In comparison with other fibers, nylon fiber has many advantages, such as good abrasion resistance, good moisture absorbency, high elastic resilience, high breaking strength, high ductility, excellent dyeing properties and low specific gravity, etc.2,3 But its thermal performance is very poor, nylon fabric is easy to combust and produce melt dripping. Those shortcomings seriously limit extensive application of nylon. So, it is vital for nylon fabric to be endowed with durable flame-retardancy. Currently, there are three technical approaches to make flame-retardant nylon. First, flame-retardant nylon can be produced by copolymerization using phosphorus-containing diamine monomers, but it has not achieved commercial success; Second, another way is to add flame-retardant additives to nylon polymers during fiber spinning; At last, flame-retardant finishing has been considered as a practical way to produce flame-retardant nylon fabrics.4-9 However, mostly used flame-retardants are halogen and formaldehyde flame-retardant system, which is harmful to the environment and human.10,11 Moreover, due to the special structure of nylon fabric, common flame-retardant is difficult to be combined with nylon fabric, resulting in poor washability of treated nylon fabric, and it is often accompanied with the application of crosslinker, while it has a bad effect on handle of fabrics.
In order to solve these problems above, we carried out studies in an effort to synthesize a new durable flame-retardant containing phosphorus and sulfur for nylon fabric. When the flame-retardant was heated, phosphate groups degraded to form phosphoric acid and make nylon cellulose change into phosphorylated cellulose, then they further decomposed to form residue (char and phosphorus oxides). At the same time, sulfur element could reduce the melting point of nylon fabric and eutectic reaction occurred between PA-FR and polyamide chain segments of nylon fabric. And the durability of this retardant system to multiple laundries was studied to conclude that it is promoted to be a durable flame-retardant. Moreover, it has no free-formaldehyde or halogen and good prospect.
2018; 42(2): 157-166
Published online Mar 25, 2018
College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
National Engineering Laboratory for Modern Silk, Suzhou 215123, China