The Impact of Novel Phosphorus-Nitrogen Flame Retardants on the Fire Resistance of Fabrics

The Impact of Novel Phosphorus-Nitrogen Flame Retardants on the Fire Resistance of Fabrics

With the increasing awareness of safety, fire-resistant materials are being widely used across various industries. Particularly in the textile industry, the fire resistance of fabrics is directly related to the safety of lives and property. In recent years, novel phosphorus-nitrogen flame retardants have become a research hotspot due to their excellent flame-retardant properties and environmental friendliness. This article explores the impact of novel phosphorus-nitrogen flame retardants on the fire resistance of fabrics from multiple perspectives, combining specific product parameters and experimental data to analyze their performance in practical applications.

1. Overview of Phosphorus-Nitrogen Flame Retardants
   1.1 Definition and Classification of Phosphorus-Nitrogen Flame Retardants
   Phosphorus-nitrogen flame retardants are a class of compounds primarily composed of phosphorus and nitrogen as flame-retardant elements. Based on their chemical structure, they can be divided into two major categories: organic phosphorus-nitrogen flame retardants and inorganic phosphorus-nitrogen flame retardants. Organic phosphorus-nitrogen flame retardants mainly include phosphates, phosphoramides, etc., while inorganic phosphorus-nitrogen flame retardants include ammonium phosphate, ammonium polyphosphate, etc.

1.2 Flame-Retardant Mechanism of Phosphorus-Nitrogen Flame Retardants
The flame-retardant mechanism of phosphorus-nitrogen flame retardants primarily includes the following aspects:
• Gas-phase flame retardancy: Phosphorus-nitrogen flame retardants decompose at high temperatures to produce phosphorus and nitrogen free radicals, which can capture active free radicals during combustion, thereby interrupting the combustion chain reaction.
• Condensed-phase flame retardancy: Phosphorus-nitrogen flame retardants form a stable char layer during combustion, isolating oxygen and heat, and preventing flame spread.
• Synergistic effect: Phosphorus and nitrogen elements work synergistically during the flame-retardant process, improving efficiency.

1. Characteristics of Novel Phosphorus-Nitrogen Flame Retardants
   2.1 Environmental Friendliness
   Novel phosphorus-nitrogen flame retardants do not produce toxic or harmful substances during production and use, meeting environmental requirements. For example, ammonium polyphosphate (APP), a common inorganic phosphorus-nitrogen flame retardant, is widely used in the textile industry due to its low toxicity, halogen-free, and smoke-free properties.

2.2 High Efficiency
Novel phosphorus-nitrogen flame retardants achieve excellent flame-retardant effects at low additive levels. Experiments show that adding 5% ammonium polyphosphate can increase the limiting oxygen index (LOI) of fabrics from 18% to over 28%.

2.3 Durability
Novel phosphorus-nitrogen flame retardants exhibit good wash resistance and weather resistance. Their flame-retardant performance remains stable even after multiple washes and prolonged exposure to natural environments.

1. Impact of Novel Phosphorus-Nitrogen Flame Retardants on the Fire Resistance of Fabrics
   3.1 Limiting Oxygen Index (LOI)
   The limiting oxygen index is an important metric for evaluating the flame-retardant performance of materials. Table 1 lists the LOI values of several common fabrics after adding different proportions of novel phosphorus-nitrogen flame retardants.

As shown in Table 1, novel phosphorus-nitrogen flame retardants can significantly increase the LOI values of fabrics, with the LOI rising as the additive amount increases.

3.2 Heat Release Rate (HRR)
The heat release rate measures the rate at which heat is released during combustion. Figure 1 shows the HRR curves of cotton fabric after adding different proportions of novel phosphorus-nitrogen flame retardants.

From Figure 1, it can be observed that adding novel phosphorus-nitrogen flame retardants significantly reduces the HRR of cotton fabric, indicating decreased heat release during combustion and improved flame-retardant performance.

3.3 Smoke Density
Smoke density measures the amount of smoke produced during combustion. Table 2 lists the smoke density values of several common fabrics after adding different proportions of novel phosphorus-nitrogen flame retardants.

As shown in Table 2, novel phosphorus-nitrogen flame retardants can significantly reduce the smoke density of fabrics, decreasing smoke production during combustion and enhancing safety.

1. Performance of Novel Phosphorus-Nitrogen Flame Retardants in Practical Applications
   4.1 Fireproof Treatment of Textiles
   Novel phosphorus-nitrogen flame retardants are widely used in the fireproof treatment of textiles. For example, in firefighting suits, military uniforms, children’s sleepwear, and other specialty textiles, adding these retardants can significantly improve fire resistance, ensuring user safety.

4.2 Fireproof Treatment of Building Materials
In building materials, novel phosphorus-nitrogen flame retardants are also extensively applied. For instance, adding them to fireproof coatings and fireproof boards can increase their fire resistance limits, reducing the risk of fires.

4.3 Fireproof Treatment of Electronic Products
In electronic products, novel phosphorus-nitrogen flame retardants are used in materials such as circuit boards and cables. Their addition can effectively prevent fires caused by high temperatures or short circuits, safeguarding both equipment and users.

1. Research Progress at Home and Abroad
   5.1 Domestic Research Progress
   Domestic researchers have made significant strides in the study of novel phosphorus-nitrogen flame retardants. For example, a university research team developed a novel organic phosphorus-nitrogen flame retardant. Tests on cotton fabric showed that adding 5% of the retardant increased the LOI to over 30%, with excellent wash resistance.

5.2 International Research Progress
International researchers have also achieved important results. For instance, an international team developed a novel inorganic phosphorus-nitrogen flame retardant. Tests on polyester fabric demonstrated that adding 10% of the retardant increased the LOI to over 35%, with a significant reduction in smoke density.

1. Future Development Directions
   6.1 Multifunctionality
   In the future, one direction for novel phosphorus-nitrogen flame retardants is multifunctionality. For example, developing retardants with additional properties such as antibacterial, anti-mold, and anti-static capabilities to meet diverse application needs.

6.2 Nanotechnology
The application of nanotechnology will bring new opportunities for the development of novel phosphorus-nitrogen flame retardants. Nanoscale processing can improve the dispersion and stability of retardants, further enhancing their efficiency.

6.3 Smart Retardants
Smart functionality is another important direction. For instance, developing intelligent flame retardants that can automatically adjust their performance based on environmental temperature to improve adaptability in practical applications.