Silk Physical and Mechanical Properties

Properties: tenacity 3.5-5.0 g/den (dry), 2.8-4.0 g/den (wet, 20% loss, better wet strength retention than cotton/wool), elongation at break 10-25%, elastic recovery 92% at 2% extension (excellent resilience, wrinkle resistant), moisture regain 11%, density 1.34 g/cm³, thermal conductivity 0.06 W/(m·K) (cool in summer, warm in winter), dielectric constant low (antistatic), UV resistance poor (degrades 50% strength after 200 hours direct sunlight), resistance to most acids (damaged by alkalis pH >10, dissolved in concentrated mineral acids), excellent drape (0.5-2 cm bending length), and characteristic luster (light refraction through triangular cross-section and molecular orientation).