Editing Dynamic mechanical analysis (section)

====Temperature sweep====
A common test method involves measuring the complex modulus at low constant frequency while varying the sample temperature. A prominent peak in <math>\tan(\delta)</math> appears at the glass transition temperature of the polymer. Secondary transitions can also be observed, which can be attributed to the temperature-dependent activation of a wide variety of chain motions.<ref name = "Young">{{cite book|last=Young|first=R.J.|author2=P.A. Lovell|title=Introduction to Polymers|publisher=Nelson Thornes|year=1991|edition=2}}</ref> In [[semi-crystalline polymer]]s, separate transitions can be observed for the crystalline and amorphous sections. Similarly, multiple transitions are often found in polymer blends.

For instance, blends of [[polycarbonate]] and poly([[acrylonitrile-butadiene-styrene]]) were studied with the intention of developing a polycarbonate-based material without polycarbonate's tendency towards [[brittle failure]]. Temperature-sweeping DMA of the blends showed two strong transitions coincident with the glass transition temperatures of PC and PABS, consistent with the finding that the two polymers were immiscible.<ref name=Mas>{{cite journal|last=J. Màs |year=2002|title=Dynamic mechanical properties of polycarbonate and acrylonitrile-butadiene-styrene copolymer blends|doi=10.1002/app.10043|journal=Journal of Applied Polymer Science|volume=83|issue=7|pages=1507–1516|display-authors=etal}}</ref>