Page 59 - Plastics News August 2019

TECHNOLOGY

PDQXIDFWXULQJ SURFHVV ,PDJLQH ORRNLQJ LQWR D ERZO RI SURYLGHG XV ZLWK D YHU\ FOHDQ ZHOO GHÀQHG V\VWHP IRU GDWD
cooked spaghetti and watching the motion of a single DQDO\VLV 7KH UHVHDUFKHUV IRXQG WKDW WKH SHUFHQWDJH RI
QRRGOH DV WKH ERZO LV PL[HG 6FKURHGHU VDLG :H IRXQG the molecular subpopulation that exhibits the two-phase
that the polymers exhibit one of two distinct relaxation relaxation behavior increases as the overall polymer
PRGHV VDLG FR DXWKRU DQG JUDGXDWH VWXGHQW <XHFKHQJ FRQFHQWUDWLRQ LQFUHDVHV LQ WKH HQWDQJOHG VROXWLRQV :H
3HWHU =KRX 2QH JURXS RI SRO\PHUV UHOD[HG YLD D VLQJOH are not certain why the single-mode relaxation or fast-
decaying exponential rate and the other group showed a retraction mode seems to be concentration-dependent,
two-phase process. That second population undergoes a but it may have to do with enhanced interpolymer friction
very quick initial retraction followed by a slow relaxation. -- the more polymers, the higher the chance they will
The existence of two different molecular populations was LQWHUDFW HVSHFLDOO\ RXW RI HTXLOLEULXP =KRX VDLG :H DUH
XQH[SHFWHG DQG QRW SUHGLFWHG E\ FODVVLF WKHRU\ 7KLV working with theorists here at the University of Illinois to
study worked with high molecular-weight DNA because better explain the single-mode and two-mode relaxation
it serves as an ideal model of other types of synthetic SKHQRPHQD 7KH WHDP LV H[FLWHG WR EULQJ QHZ LQVLJKW WR
RUJDQLF SRO\PHUV WKH UHVHDUFKHUV VDLG :H FKRVH '1$ DV WKH XQGHUVWDQGLQJ RI KRZ FRPSOH[ ÁXLGV ÁRZ DQG KRZ
our model polymer because it is a very large molecule and they are processed and manufactured, especially with
WKH FKDLQV DUH ELJ HQRXJK WR LPDJH LQ RXU PLFURVFRSH polymers that are subjected to intense stress, such as the
6FKURHGHU VDLG 7KH\ DUH DOVR DOO WKH VDPH ZHLJKW ZKLFK ÁXLGV WKDW DUH XVHG IRU ' SULQWLQJ

59
61 August 2019 Plastics News