Prediction of the Glass Transition Temperature of Multicyclic and Bulky Substituted Acrylate and Methacrylate Polymers Using the Energy, Volume, Mass (EVM) QSPR Model

1996 ◽  
Vol 29 (27) ◽  
pp. 8954-8959 ◽  
Author(s):  
Christopher C. Cypcar ◽  
Philippe Camelio ◽  
Veronique Lazzeri ◽  
Lon J. Mathias ◽  
Bernard Waegell
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Qspr Model ◽  
Methacrylate Polymers

Structure and Dynamics of Syndiotactic Poly(n-Butyl Methacrylate) Near the Glass Transition

1990 ◽  
Vol 215 ◽  
Author(s):  
G. D. Paiterson ◽  
P. K. Jue ◽  
J. R. Stevens
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Relaxation Function ◽  
Butyl Methacrylate ◽  
Time Range ◽  
Pure Liquid ◽  
Relaxation Rates ◽  
Relaxation Functions ◽  
Methacrylate Polymers

AbstractAn optically homogeneous sample of highly syndiotactic poly(n-butyl methacrylate) (PBMA) has been prepared. The glass transition temperature was observed to be Tg=55C. Measurements of the scattered intensity of the sample followed the expected behavior for a pure liquid above Tg. The intensity rose as the sample was cooled further towards the glass transition temperature for atactic PBMA. These results illuminate the importance of regions of different stereoisomers in methacrylate polymers. Measurements of the Rayleigh- Brillouin spectrum were carried out from -15 to 130 C. The ratio of the the central peak intensity to the Brillouin intensities at temperatures above Tg was consistent with a viscoelastic liquid and had a magnitude near 3. The Brillouin linewidth remained large near Tg. and decreased continuosly with no apparent change in slope in the glass transition region. The presence and importance of rapid motions in polymers near the glass transistion is demonstrated by these results. Slowly relaxing density fluctuations near Tg. were measured by photon correlation spectroscopy. Relaxation functions were obtained from 10−6 to 10 s. Average relaxation times <τ> were obtained from the integral of the relaxation function and were found to follow the relation <τ>=Aexp(B/(T−T0)), where for our sample B=2940K and T0=273K. The observed relaxation function decayed over a wider time range as the sample was cooled. Quantitative analysis of this effect using the Williams-Watts empirical function yielded a decrease in β from 0.35 at 90 C to 0.18 at 65 C. The relaxation functions were also analyzed to give a distribution of relaxation rates. The observed distributions were bimodal at 70 and 80 C. The two features behaved in a manner consistent with the primary and secondary relaxations observed for methacrylate polymers by other techniques.

Modeling the Glass Transition Temperature of Polymers via Multipole Moments Using Support Vector Regression

2012 ◽  
Vol 455-456 ◽  
pp. 430-435 ◽  
Author(s):  
J.F. Pei ◽  
C.Z. Cai ◽  
X.J. Zhu ◽  
G.L. Wang ◽  
B. Yan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Support Vector Regression ◽  
Percentage Error ◽  
Support Vector ◽  
Structure Property ◽  
Multipole Moments ◽  
Quantum Chemical Descriptors ◽  
Qspr Model

. This study introduces support vector regression (SVR) approach to model the relationship between the glass transition temperature (Tg) and multipole moments for polymers. SVR was trained and tested via 60 samples by using two quantum chemical descriptors including the molecular traceless quadrupole moment and the molecular average hexadecapole moment Φ. The prediction performance of SVR was compared with that of reported quantitative structure property relationship (QSPR) model. The results show that the mean absolute error (MAE), mean absolute percentage error (MAPE) and root mean square error (RMSE) of training samples and test samples achieved by SVR model, are smaller than those achieved by the QSPR model, respectively. This investigation reveals that SVR-based modeling is a practically useful tool in prediction of the glass transition temperature of polymers.

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