THERMOMECHANICAL ANALYSIS IN TEXTILE TESTING - METHODOLOGY AND APPLICATION - Part II - 4. Determination of the Shrinkage Force Behavior of Synthetic Fibers

Sep 28, 2026

Thermomechanical analysis for textile testing is presented, focusing on measuring shrinkage-force behavior of fibers, yarns, and fabric strips. A recording device is described that combines clamping and controlled tension, heat application, and force measurement, including the ability to set overfeed conditions. The text explains how length variations and fine extension adjustments enable controlled equilibrium tension during measurement. It further discusses temperature-dependent shrinkage-force diagrams for polyester filament yarns, including qualitative assessment from comparison curves and determination of effective pretreatment tension and temperature via controlled preload and related temperature zones.

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THERMOMECHANICAL ANALYSIS IN TEXTILE TESTING - METHODOLOGY AND APPLICATION

4. Determination of the Shrinkage Force Behavior of Synthetic Fibers

4.1. Shrinkage Force Measurements on Polyester Filament Yarns with Different Pretreatment Histories

4.2. Determination of the Equilibrium Shrinkage Force of Synthetic Fibers

Berndt,H.J. # Thermomechanical analysis in textile testing -methodology and application.Pet乙，14 p. Text.Prax.Int.39:46-50(Jan.,1984)·Filed: TRANSLATION NO.4472T×P0AT Text. Prax. Int. 39,46-50(Jan.1984) (6: 工 □ N ## THERMOMECHANICAL ANALYSIS IN TEXTILE TEST ING-METHODOLOGY AND APPLICATION H. J. Berndt Dedicated to Dr.H.Berg on his 60th Birthday Part II* ## 4.Determination of the Shrinkage Force Behavior of SyntheticFibers A device for recording the shrinkage forces of fibers,yarns,and strips □f fabric is shown schematical¹y in Figure 11. The equipment combines a means of c1amping and applyingtension, a means □f applying heat,as wel1 as a means □fmeasuring the force; it shou1d a1so be possible of settingcertain amounts of overfeed. What has been said regarding Fig.3also applies to the first two elements mentioned above. Device for Measuring Force:This mLst operate withminimLum inertia andminimum movement. Its range of fcrcemeasurementmLIst beapplicable to the shrinkage forces to beexpectedin eachCase. Experience has shown that ithmaterial from croSs-Woundbobbins one must plan for a maximumshrinkage force of △ to 8cN/tex. Allcwing forLength Variations: This part of the setupis required in order to provide a certain overfeed or preloaci atthebeginning ofthetest,or, when measuring equilibriumshrinkage forces,tocontinuously provide tension equilibriLmduringthe measLrementprocedure throughthe application ofpositive or negative overfeed. Since these steps are only toproducesdifferences intension of about 0.1 cN/tex,a fine Digitized by the Internet Archivein 2019 https://archive.org/details/thermomechanical00bern_0 2 adjustment of the appliedextension is required, capable ofextension steps of the order of about 0.1%. As Figure 12 illustrates, the shrinkage force of amaterial overthe entire measLred temperature range isinfluenced by the tension at the beginning of the test.Consequent1y the recorded shrinkage forces can supply on1ysLmmary information regarding the restoration forces devel opingwith rising temperature and the tensions applied externally. ### 4.1.Shrinkage Force MeasLrements on PolyesterFilamentYarns with Different Fretreatment Histories FigLure13 shoWStemperature-dependent shrinkageforcediagrams forthe same test samples which served as the basisforFigure8.From these diagrams one candeduce thosetensionstobe expected in a material which has undergonethermal treatmentat constant length. With this techni qL.e onearrive in thelaboratory at the preload necessary to achieve acertainshrinkage force, or extremely high shrinkageforceswi11 be indicated at the right time. The measurement curves themselves enable only qualitativeassertions to be made concerning the state □f the material.Through comparison with other shrinkage force curves, one maydraw,from the amplitude of the shrinkage forces at comparabletemperatures or the temperature zone of the shrinkage forcemaximLIm:conclusions regardingtensionortemperatureabnormalitiesinthe pretreatment:absolute aSsertionsregardingthether mal.pretreatmentareanalogous withshrinkagemeasLurement,possible throughLIse□fthefirstderivative□f七hetemperature-shrinkage force curve[137.Theeffectivetension ofthe pretreatmentcan bedetermined fromthe temperature-dependentrecorded shrinkage force diagram,bya serie生□ftests per FigLre 13 in whichthe preload is raisedS0highthatimmediatelybeforereachingthe effectivetemperature□fthepretreatmentaSdetermined byDTAmeasLrements:constant tensionexists □vera range of at least3 to5-C,thatistosay Lintilanalogousto thedetermination□feffective tensionby lcading tests, theexterna1.1y applied testtensions arein equilibrium with theinternal tensions released duringthemeasLring procedure E14].In the case of the polyesterfilamentyarn serving as basis forFigure 13,this equilibrium,for example,is reached at a testtemperature below190C andat ashrinkage force of 2cN/tex, the initial tensionhavingbeen raisedto

FAQs

What components are combined in the device for recording fiber shrinkage forces?

The equipment combines means of clamping and applying tension, applying heat, and measuring the force.

Why is adjustment of applied extension necessary in shrinkage-force testing?

Because the overfeed or preload steps produce only small tension differences (about 0.1 cN/tex), a fine adjustment of the extension is required, typically in steps of about 0.1%.

How are temperature-dependent shrinkage-force diagrams used for polyester filament yarn pretreatment?

The diagrams allow inference of expected tensions for materials treated at constant length, enabling qualitative conclusions and, through controlled preload and comparison with effective pretreatment temperature zones, determination of effective pretreatment tension.

Sep 28, 2026

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