Properties of Synthetic Fiber

Synthetic fibers have revolutionized the textile industry, offering a wide range of properties that often differ significantly from natural fibers like cellulose and protein fibers. Understanding these differences is crucial for selecting the right materials for various applications, from clothing to industrial uses. This article will explore the key performance characteristics of synthetic fibers, highlighting their advantages and disadvantages compared to their natural counterparts.

1. Strength, Durability, and Abrasion Resistance

Synthetic fibers generally exhibit superior strength, durability, and abrasion resistance compared to natural and artificial fibers. This makes them ideal for applications requiring robust materials.

• High Strength: Synthetic fibers can withstand significant pulling forces without breaking.
• Excellent Durability: They are resistant to wear and tear, ensuring longevity.
• Superior Abrasion Resistance: The ability to resist surface wear from rubbing or friction.

For example, nylon is often used to reinforce collars, cuffs, and waistbands in knitwear, providing both durability and elasticity. Nylon elastic yarns are particularly popular in hosiery, gloves, and elastic shirts due to their exceptional wear resistance and stretch.

2. Moisture Absorption and Breathability

A major drawback of many synthetic fibers is their poor moisture absorption, leading to reduced breathability and discomfort, especially in warm weather.

• Low Moisture Absorption: Synthetic fibers do not readily absorb moisture, leading to a build-up of sweat and humidity next to the skin.
• Poor Breathability: They restrict air circulation, exacerbating the discomfort caused by low moisture absorption.

As a result, synthetic fibers are rarely used for innerwear where comfort is paramount.

3. Shrinkage, Drying Time, and Elasticity

Synthetic fibers offer several advantages in terms of dimensional stability and ease of care:

• Minimal Shrinkage: They are resistant to shrinkage, maintaining their size and shape after washing.
• Quick Drying: Synthetic fabrics dry rapidly due to their low moisture absorption.
• Good Elasticity: Synthetic fibers have excellent stretch and recovery, resisting wrinkles.

These properties make them “wash-and-wear” fabrics, requiring little or no ironing after washing.

4. Static Electricity and Soil Adsorption

Synthetic fibers are prone to static electricity build-up, leading to other issues:

• Static Electricity: Synthetic materials readily develop static charges, especially in dry conditions.
• Soil Adsorption: Static charges attract dust and dirt, causing fabrics to become soiled quickly.

5. Melting Characteristics

Synthetic fibers are susceptible to melting when exposed to high temperatures or direct flame:

• Melting Point: They can melt or form holes when exposed to sparks, embers, or welding flashes.
• Softening Point: The softening temperatures of synthetic fibers generally range from 170°C to 250°C (with chlorofiber softening at 60°C-90°C).
• Risk of Damage: Embers and sparks, often exceeding 400°C, can easily damage synthetic fabrics.

6. Pilling and Fuzzing

Pilling and fuzzing are common problems with synthetic fabrics, detracting from their appearance:

• Pilling: Small balls of fiber form on the fabric surface due to abrasion.
• Fuzzing: Loose fibers protrude from the fabric, creating a fuzzy texture.

Knitted fabrics are more prone to pilling and fuzzing than woven fabrics. Pilling can make garments look dirty and worn, necessitating the use of depilling devices.

7. Thermal Insulation

While traditionally natural wool was considered best, some synthetic fibers can provide superior thermal insulation:

• High Thermal Insulation: Certain synthetic fibers offer excellent warmth, rivaling or surpassing that of natural fibers.
• Chlorofiber: Chlorofiber’s insulation can exceed wool’s by 10%-260% and cotton’s by 50%.
• Other synthetics: Vinylon and acrylic fibers also provide excellent warmth, especially compared to cotton and viscose.

8. Heat Resistance

Generally, synthetic fibers have low heat resistance compared to natural fibers:

• Poor Heat Resistance: They cannot withstand high temperatures during washing or ironing.
• Risk of Damage: High heat can cause them to shrink, melt, or deform.

9. Sunlight Resistance

Sunlight resistance varies significantly among synthetic fibers:

• Varied Performance: While most synthetic fibers outperform cellulose and protein fibers in sunlight resistance, the difference is significant.
• Best vs Worst: Modacrylic exhibits exceptional sunlight resistance, whereas nylon is the least resistant.

Comparison of Synthetic Fiber Properties

The following table summarizes the key properties of various synthetic fibers:

Property	Polyester	Nylon	Acrylic	Polypropylene	Vinylon	Spandex
Sunlight Resistance	Second best	Fairly good	Best	Excellent	Good	Good
Acid Resistance	Stable to most acids	Decomposes in strong acids	Stable to most acids	Good resistance to most acids	Insoluble in weak acids	Stable to most acids
Alkali Resistance	Sensitive to alkalis	Resistant to strong alkalis in cool water	Moderate	Resistant	Slightly affected by 50% NaOH	Stable to strong alkalis
Bleach Resistance	Good	Good	Good	Excellent	Good	Poor (yellows)
Oxidation Resistance	Good	Good	Good	Excellent	Good	Fairly good
Abrasion Resistance	Good	Best	Fairly good	Excellent	Excellent	Strong
Moth Resistance	Good	Resistant, but susceptible to mildew	Good	Good	Good	Good
Dyeability	Disperse dyes (high pressure, high temperature)	Acid and disperse dyes	Not easily dyed (solution dyeing or fiber modification)	Solution dyeing	Direct and vat dyes	Acid dyes, disperse dyes
Reducing Agent Resistance	Strong	Weak	Strong	Poor	Strong	Strong

Synthetic fibers offer a diverse range of properties, each with its own advantages and disadvantages. Understanding these characteristics is essential for selecting the appropriate fiber for specific applications, balancing performance needs with comfort and aesthetics.