Editing Gore-Tex (section)

== Structure ==
ePTFE has a porous microstructure composed of long, narrow fibrils that intersect at nodes. Increasing the processing temperature or increasing the strain rate leads to more homogenous expansion with more spherically symmetric pores and more intersections between fibrils.<ref name=":0">{{cite book |last1=Ebnesajjad |first1=Sina |title=Expanded PTFE Applications Handbook |date=2017 |publisher=Elsevier Inc. |isbn=978-1-4377-7855-7}}</ref> The formation of ePTFE is enabled by the unwinding of PTFE molecules to create large pores within the structure. This favors highly ordered, crystalline PTFE that allows the molecules to disentangle more easily and uniformly when stretched. The porosity is largely determined by the stretching temperature and rate. Changing the stretching rate from 4.8 m/min to 8m/min can increase the porosity from 60.4% to 70.8%.<ref>{{cite journal |last1=Hao |first1=Xinmin |last2=Zhang |first2=Jianchunn |last3=Guo |first3=Yuhai |last4=Zhang |first4=Huapeng |title=Studies on Porous and Morphological Structures of Expanded PTFE Membrane through Biaxial Stretching Technique |journal=Journal of Engineered Fibers and Fabrics |date=June 2005 |volume=14 |issue=2 |doi=10.1177/1558925005os-1400205 |s2cid=53348676 |doi-access=free }}</ref>