0 Waldow, Dean Wolbrecht, Steven Dadmun, Mark 2008 Macromolecular Theory and Simulations Submitted Copolymer additives of different molecular weights and structures in a polymer blend were studied using Monte Carlo simulations with a focus on the phase separated interface. The copolymers migrate to the interface with molecular weight having only modest affect. The shape of the copolymers at the interface was a strong function of their structure with most copolymers spread out oblate along the interface while the diblocks became prolate protruding into the two phases. The copolymer volume was also dependent on the copolymer structure with larger copolymers experiencing an increase in their volume with quench depth whereas the random copolymer experienced a reduction in volume. The aggregate results suggest that ran-block copolymers show strong potential as effective compatibilizers for polymer blends. Submitted to Macromolecular Theory and Simulations on May 12, 2008 0 Voge, Gretchen Fosser, Kari Waldow, Dean Briber, Robert Halasa, Adel 2004 Journal of Polymer Science, Part B: Polymer Physics 42 3191-3203 2004717385 Small-angle neutron scattering (SANS) has been employed to study a blend of polystyrene and polybutadiene modified by copolymer additives. SANS data from the one-phase region approaching the phase boundary has been acquired for blends modified by random and diblock copolymers that have equal amts. of styrene and butadiene monomers as well as a random copolymer with an unequal monomer compn. The binary blend is near the crit. compn., and the copolymer concns. are low at 2.5% (wt./wt.). The data have been fitted with the RPA model (binary and multicomponent versions) to obtain Flory-Huggins interaction parameters (.chi.) for the various monomer interactions. These results are considered in the context of previous light scattering data for the same blend systems. The SANS cloud points are in good agreement with previous results from light scattering. The shifts in the phase boundary are due to the effects of the additives on the .chi. parameter at the spinodal. All the additives appear to lower the .chi. parameter between the homopolymers; this is in conflict with the predicted Flory-Huggins behavior. 0 Waldow, Dean 2002 Journal of Chemical Education 79 561-562 2002306453 Abstract Unavailable Advance information prior to publication in Chemical Abstracts 0 Barham, Bethany Fosser, Kari Voge, Gretchen Waldow, Dean Halasa, Adel 2001 Macromolecules 34 514-521 20014881 The phase sepn. behavior of blends of polystyrene and polybutadiene modified by copolymer additives was studied using light scattering techniques. Block and random copolymers with equal styrene and butadiene content and a random copolymer with unequal monomer compn. were used as additives at a concn. of 2.5%. The sym. additives lowered the phase boundary with increasing concn. while the asym. additive destabilized the phase boundary. The data demonstrate a slowing of the kinetics with the addn. of any of the copolymers. In comparison to the binary blend, droplet sizes in the early stage were smaller with added sym. block copolymer and larger with added asym. random copolymer. Scaling anal. of the intermediate stage kinetics showed some deviations relative to binary scaling results. Deviations from Porod's law indicate that modifications to the interfacial boundary are most notable for the asym. random copolymer. Self-similarity was seen to hold for all of the systems. 0 Dadmun, M. D. Waldow, Dean 1999 Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics 60 4545-4550 36-6 (Physical Properties of Synthetic High Polymers), Monte Carlo simulation polymer blend property, Polymer blend compatibilizers, Polymer blends, RL: POF (Polymer in formulation), PRP (Properties), USES (Uses), Simulation and Modeling, physicochemical Monte Carlo simulation and finite-size anal. are used to det. the crit. properties of a binary homopolymer blend and of a polymer blend that is compatibilized with a random copolymer. Detn. of _, the crit. exponent for the correlation length, for the mixt. of two homopolymers shows that the binary blend exhibits properties that are consistent with Ising behavior (_ = 0.63). Similar results for the compatibilized blend show that the added copolymer acts very much like an impurity; lowering the mixing transition temp. and increasing the value of _ to a value that is in qual. agreement with Fisher renormalization (_ = 0.69). These results are important as copolymers are often added to polymer blends to act as compatibilizers. These results show that the anal. of the phase behavior of these mixts. must be done with the understanding that its crit. exponents differ from those of a binary polymer mixt. 0 Waldow, Dean A. Fryhle, Craig B. Bock, J. Chris 1997 Journal of Chemical Education 74 441-442 1997184858 The CIRRUS chem. Internet resource is presented for undergraduate student chem. research. 0 Fryhle, Craig B. Waldow, Dean A. Bock, J. Chris 1997 Journal of Chemical Education 74 442-443 1997184860 Undergraduate instruction in FT NMR spectrometry is described using the FTNMR Free Induction Decay Archive for processing on personal computers. 0 Fryhle, Craig B. Waldow, Dean A. Bock, J. Chris 1997 Journal of Chemical Education 74 442 0 Dean A. Waldow Craig B. Fryhle J. Chris Bock 1995 In Chemistry 6 14 0 Nakatani, Alan I. Waldow, Dean A. Han, Charles C. 1992 Review of Scientific Instruments 63 3590-8 1992449686 A combined rheometer and light scattering photometer is constructed to examine the light scattering behavior of polymer melts and solns. under the influence of a simple shear field. The device utilizes a special lens system and a 2-dimensional charge-coupled device array detector which has not been used previously in an app. of this type to quant. measure the scattering intensity as a function of shear rate. The accessible q range of the instrument is from 3.75 .times. 10-4 to 3.0 .times. 10-3 nm-1 (2.2.degree.-17.4.degree. scattering angle, with .lambda. = 632.8 nm). The rheometer uses a cone and plate geometry to generate the shear gradient and is capable of measuring torque (1.8 N m max.) and normal forces (50 N max.). An 8% soln. of a 50:50 polystyrene/polybutadiene blend in dioctyl phthalate was used to test the app. This sample shows a shear-induced mixing behavior which is consistent with previous measurements by other investigators. 0 Waldow, Dean A. Nakatani, Alan I. Han, Charles C. 1992 Polymer 33 4635-8 1992652289 A light scattering instrument capable of monitoring the scattering from samples under the influence of a simple shear field is constructed. The app. consists of transparent cone-and-plate fixtures. and a two-dimensional charge coupled device array detector. The detector unit is also capable of measuring the scattering patterns as a function of time. The phase sepn. kinetics of an 8% soln. of a polystyrene-polybutadiene (50:50) blend in dioctyl phthalate following cessation of a steady shear is monitored with this instrument. The sample is two-phase in the quiescent state and the applied shear is sufficient to suppress all scattering obsd. from the quiescent sample (shear-induced mixing). The evolution of the scattering profiles following cessation of shear is quite different parallel and perpendicular to the original flow direction. In the normal direction, a spinodal growth and coarsening mechanism similar to that obsd. in temp. quench expts. is obsd. In the parallel direction, a different mechanism is followed. 0 Hammouda, B. Nakatani, A. I. Waldow, D. A. Han, C. C. 1992 Macromolecules 25 2903-6 1992236563 Small-angle neutron scattering of high-mol.-wt. (1.95 x 106) polystyrene in dioctyl phthalate solns. was measured at low concn. (3% wt. fraction) under steady shear with rates ranging from the quiescent condition (0 s-1) to 1100 s-1 at room temp. (22.degree.). The scattered intensity increased dramatically beyond a characteristic shear rate (.gamma.c = 57 s-1) similar to the increase following a temp. drop from the one-phase region (ambient temp.) to the two-phase region in this upper crit. soln. temp. system. The RPA approach (the Zimm inverse scattering formula) was used along with a swollen radius of gyration in the Debye function to analyze the data and ext. a statistical segment length b and a polymer-solvent interaction parameter .CHI.ps. The segment length increased slightly, indicating a slight increase in chain vol. beyond .gamma.c, while the interaction parameter showed a dramatic increase up to the spinodal value .gamma.s = 280 s-1 where the RPA breaks down, therefore giving nonreliable values. 0 Waldow, Dean A. Ediger, M. D. Yamaguchi, Yoshikazu Matsushita, Yushu Noda, Ichiro 1991 Macromolecules 24 3147-53 1991229879 The local segmental dynamics of anthracene-labeled polystyrene in dil. soln. was studied using time-correlated single-photon counting. Six solvents covering 2 decades in viscosity (.eta.) were utilized. Correlation times were extd. from the orientation autocorrelation functions and detd. as a function of temp. in all solvents. Under good solvent conditions, the correlation time is proportional to .eta.0.9 at const. temp., in reasonable agreement with the .eta.1.0 prediction of the Kramers' equation in the high-friction limit. Other aspects of the results are also reasonably consistent with the assumption that the solvent acts as a continuum. Somewhat slower dynamics are obsd. in .THETA. solvents than in good solvents. The potential barrier height for local dynamics extd. from these measurements is .+-. 3 kJ/mol. 0 Waldow, Dean A. Kim, Hongdoo Han, Charles C. Qui, Tran Cong Yamamoto, Masahide 1990 Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) 31 145-6 1991186528 The temp. dependence of diffusion of tetraethyl[3.3]-1,4-naphthaleno-9,10-anthracenophane-2,2,15,15-tetracarboxylate (a cyclophane dye) in polystyrene, poly(vinyl acetate), and poly(vinyl Me ether) matrixes was studied. The effect of polymer glass temp. on the diffusion coeffs. follows a universal functional form which is well represented by the Williams-Landel-Ferry equation. 0 Waldow, Dean A. Johnson, Brian S. Hyde, Patrick D. Ediger, M. D. Kitano, Toshiaki Ito, Koichi 1989 Macromolecules 22 1345-51 1989136139 Solvent quality affected the local dynamics of anthracene-labeled polyisoprene in dil. soln. by changing the local segment concn. in the vicinity of the labeled segment. The local dynamics in a .THETA. solvent exhibited a mol. wt. dependence not obsd. in good solvents. The shape of the orientation autocorrelation function obtained from ps holog. grating techniques was const. under all conditions investigated. These results were consistent with the hypothesis that local segmental dynamics in dil. soln. depended only on solvent viscosity and solvent thermodn. power. 0 Waldow, Dean A. Hyde, Patrick D. Ediger, M. D. Kitano, Toshiaki Ito, Koichi 1987 ACS Symposium Series 358 68-82 1988132614 A picosecond holog. grating technique was used to observe the local segmental dynamics of anthracene (I)-labeled polyisoprene (II) in dil. hexane, cyclohexane, and 2-pentanone solns. The transition dipole of the I label lies along the chain backbone, assuring that only backbone motions are detected. Exptl. measurements of the orientation autocorrelation function of a backbone bond are compared with theor. predictions. The obsd. correlation functions are consisted with models proposed by Hall and Hilfand and Bendler and Yaris. Anal. of the temp. dependence of the correlation function yielded an activation energy of .apprx.7 kJ/mol for local segmental motions. 0 Hyde, Patrick D. Waldow, Dean A. Ediger, M. D. Kitano, Toshiaki Ito, Koichi 1986 Macromolecules 19 2533-8 1986573482 A picosecond holog. grating technique was used to observe the local segmental dynamics of anthracene-labeled polyisoprene in dil. hexane and cyclohexane solns. The transition dipole of the anthracene label lies along the chain backbone, ensuring that only backbone motions are detected. The exptl. observable, the orientation autocorrelation function of a backbone bond, is compared with theor. predictions. The obsd. correlation functions are consistent with models proposed by Hall and Helfand and by Bendler and Yaris. The correlation functions for the 2 solvents have the same shape within exptl. error while the time scale of the decays varies roughly with the solvent viscosity. The correlation function decays on a subnanosecond time scale in both solvents. 0 Waldow, Dean A. Hyde, Patrick D. Ediger, M. D. Kitano, Toshiaki 1986 Polymer Preprints (American Chemical Society, Division of Polymer Chemistry) 27 299-300 1986573487 The fundamental anisotropy and time consts. for correlated and isolated transitions in polyisoprene [9003-31-0] chains were detd. on a subnanosecond time scale from measurements on anthracene moiety-contg. polymer using a transient holog. grating technique. 2 Waldow, Dean Alan 1989 Madison, WI Univ. Wisconsin 1990441775 Physical Properties of Synthetic High Polymers Abstract Unavailable Avail. Univ. Microfilms Int., Order No. DA8923402