Castiglia, Silvia Regina Vitale

Fioretto, Daniele

Samios, Dimitrios

Silveira, Nádya Pesce da

Verdini, Livio

English

Lume 5.8

4º CONGRESSO BRASILEIRO DE POLÍMEROS Promoção: Salvador, 28 de setembro a 2 de outubro de 1997 4º CONGRESSO BRASILEIRQ DEPOLIMERO Associação Brasileira de Polímeros NETWORK FORMATION PROCESS OF 1,4-BUTANEDIOL DIGLYCIDYLETHER WITH CIS-1,2-CYCLOHEXANEDICARBOXYLIC ANHYDRIDE BYTEMPERATURE SCANNING BRILLOUIN SCATTERINGSílvia Castiglia+*, D. Fioretto*, Livio Verdini*, N. Pesce da Silveira+ and Dimitrios Samios++Instituto de Química/UFRGS - Cx. Postal 15003   CEP: 91501-970 Porto Alegre/RS - Brasil*Universitá degli Studi di Perugia - Departimento di Fisica - via A.Pascoli, 06100, Perugia - ItáliaIntroductionThe dynamics of curing process of 1,4-butanediol diglycidyl ether (EP) with  cis-1,2-cyclohexanedicarboxylic anhydride (CH) and the initiator triethylamine (TEA) has beenstudied  by  Temperature  Scanning  Brillouin  Spectroscopy  technique  (TSBS).1 In  thisexperiment the frequency shift (B) and width (B) of the Brillouin lines are related to thehypersound  velocity  (U),  which  is  a  time-  and  temperature-dependent  property.  Thedrastic phase change observed during the network formation enables the choice of thehypersound velocity as an observable for the reaction kinetics. A series of samples withratios of molar fraction (X  = XCH/XEP)  ranging from 0.50 to 10.08 and constant TEAconcentration was investigated. The obtained U was used as an indicator of the extent ofthe reaction through a conversion factor (), which was determined by relating the initialand the final hypersound velocities of the cure process.ExperimentalThe EP, CH and TEA were provided by Aldrich Chemical with p.a. purity. The sampleswere prepared with a ratio X = XCH/XEP ranging from 0.50 to 10.08. The liquid mixtures ofCH e EP were filtered through a 0.22-m Millipore filter into the light scattering cuvettesin order to remove dust. During the TSBS measurements every sample was submitted toa temperature scanning with a heating rate of 1 oC/min1. The temperature ranged from 30oC to 190 oC. A series of spectra were registered. The backscattered light (approx.   =180o) was analyzed in the polarized scattering geometry with a piezoelectrically scannedtriple-pass  Tandem  Fabry-Perot  Interferometer2.  The  parameters  B and  B  werecomputed by a fit of the spectra with a Lorentzian function.Results and DiscussionThe B and B of the Brillouin lines can be related to the hypersound velocity U and tothe absorption coefficient  as follow:U = B/K  = 2B/U,were  K is  defined  as  the  scattering  wave  vector1.  The  determined  U values  for  thesamples with X  between 2.20 and 10.08 are shown in Figure 1.a. A drastic decrease ofthe slope dU/dT can be observed with increasing X. The temperature dependence of theinitial and final  U in this series is affected by the composition of the initial and finalsystem.  The extent  of  the  cure  process  was  obtained in  an active  temperature  rangebetween the minimum and the maximum experimental values of U (Umin and Umax).The  relative  conversion  factor  rel for  all  the  samples  compositions  (X)  could  bedetermined taking in consideration the  Umin and  Umax for the hypersonic velocity of themeasured system and Umin and Umax of the standard sample (X = 2.20):Umax(X) - Umin(X) = .1Umax(2.20) - Umin(2.20)The values of rel were plotted vs. the molar fraction ratio X in Figure 1.b.Figure 1. a) Hypersonic velocity curves vs. temperature for different molar fraction ratio (X = XCH/XEP) b) Final relative conversion factors rel vs. molar fraction ratio (X = XCH/XEP).The data and the behavior obtained by the recently introduced TSBS technique1 suggestthat this new experimental technique demonstrates a high sensitivity and capability forthe study of curing and generally phase change including gelification and vitrificationprocesses.References1. D.Samios, S. Castiglia, N. P. da Silveira, H. Stassen, J. of Polymer Science: Part B, 1995, 33, 1857.2. D. Fioretto, L. Palmieri, G. Socino, L. Verdini, Phys. Rev. B, 1994, 50 (1), 605.AcknowledgementsS. Castiglia acknowledges a Ph. D. fellowship from CAPES. 20 50 100 150 200100012001400160018002000(1.a) 2.203.003.705.016.358.0010.08U ( m/s )Temperature ( oC)0 2 4 6 8 10 12-0.20.00.20.40.60.81.01.2(1.b)Relative  conversion  factorXCH  / XE P

Network formation process of 1,4-butanediol diglycidyl ether with cis-1,2-cyclohexanedicarboxylic anhydride by temperature scanning brillouin scattering

https://lume.ufrgs.br/bitstream/10183/266851/1/000155467.pdf

Network formation process of 1,4-butanediol diglycidyl ether with cis-1,2-cyclohexanedicarboxylic anhydride by temperature scanning brillouin scattering

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