Calculating Chemical Cross-Link Density Effects on Trapped Shear Modulus
Trapped shear modulus rises linearly with chemical cross-link density while interstitial woven constraint scales effective shear stiffness by factor 1.4 to 2.2.
Rubber Elastic Torque
Torsional Resistance
The rotational resistance exerted by an elastomeric core yarn during twisting determines the structural stability of composite linen yarns. In composite spinning, rubber elastic torque is the torsional force generated when the stretched rubber core resists the helical winding of the outer flax sheath. This mechanical tension must be carefully measured to prevent the finished yarn from snarling or curling during knitting and loom processes.
The resistance arises from the long-chain polymers of the rubber reverting to their random, high-entropy state after being drafted.
Spinning Integration
Core-spinning frames feed the elastomer strand under tension directly into the front nip of the drafting rollers. When the rubber elastic torque exceeds the holding capacity of the surrounding flax fibres, the core slips or causes uneven yarn density. Spinners adjust the draft ratio of the rubber core to control this twist-retraction behavior.
Yarn Stability
High residual torque in elastomeric linen yarns causes the finished cloth to distort or pucker during the finishing process. If the rubber elastic torque is not balanced through thermal setting, the yarn will untwist and cause skewing in the final product. Mills use steam-conditioning chambers to relax these internal forces before the yarn is sent to the loom assembly.