Specific interactions in dilute polymer solutions

Simionescu, Bogdan C.; Ioan, Catalina; Ioan, Silvia; Simionescu, C. I.

doi:10.1002/masy.19950980194

Cited by 4 publications

(3 citation statements)

References 38 publications

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“…Simionescu [1,2] et al have found a three-slope behaviour plotting the first normal stress vs. shear rate for ultra-high molar mass PMMA, measured by rheo-mechanical devices. Although a similar behaviour can recognise also in some of our plots a hypothesis test is more in favour for a simple linear behaviour.…”

Section: Discussionmentioning

confidence: 99%

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Rheo-mechanical and rheo-optical characterisation of ultra high molecular mass poly(methylmethacrylate) in solution

Dell'Erba¹

2001

Polymer

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This paper presents rheo-mechanical and rheo-optical experimental characterisation of ultra-high molecular mass poly(methylmethacrylate) in solution. A set of ultra-high molecular mass (up to 2 × 10 7 g=mol poly(methylmethacrylate), obtained in a previous work by B. Simionescu, was used together with a commercial set of lower molecular mass samples in order to cover two decades of molecular mass range. Two solvents were selected, toluene and N,N-dimethylformamide and the concentration was fixed at 2% (wt/wt). All the measurements were performed at 298ЊK.A complete rheo-mechanical characterisation, both in dynamic mode and in steady shear rate, was performed. In a second step, rheooptical techniques were able to measure the flow-induced birefringence, dichroism and the associated orientation angles. Using the experimental data obtained in this paper, we have derived the stress optical coefficients and shown that they are independent of shear rate and molar mass. We also explore the normal stress behaviour of the solutions tested. ᭧

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Section: Discussionmentioning

confidence: 99%

“…Simionescu [1,2] has measured the first normal stress difference, N 1 , vs. shear rate for poly(methylmethacrylate) (PMMA) of M w at about 2 × 10 7 g=mol in toluene at 2 and 6 (wt/wt) concentrations. He reported the presence of a three slope curve in the plot.…”

Section: Introductionmentioning

confidence: 99%

Rheo-mechanical and rheo-optical characterisation of ultra high molecular mass poly(methylmethacrylate) in solution

Dell'Erba¹

2001

Polymer

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“…Kobayashi, Sae-gusa and coworkers 7,8) have widely investigated the surfactant properties of the block and graft copolymers based on poly[(acylimino)ethylene]s. Krieger and his research group 9) reported the use of such block copolymers (i. e. poly[(p-tert-butylbenzoylimino)ethylene]block-poly[(propionylimino)ethylene] or poly[(lauroylimino)ethylene]-block-poly[(propionylimino)ethylene] as emulsifiers for inverse (salt-in-oil) emulsions. In a previous paper 10) , the ability of triblock copolymers with poly[(acetylimino)ethylene] (PNAI) central blocks and polyvinyl end blocks to stabilize water-in-oil or inverse emulsions was reported. The present report deals with the investigation of the emulsion polymerization of some vinyl monomers using graft and block copolymers with polysiloxane and PNAI sequences as polymeric stabilizers.…”

Section: Introductionmentioning

confidence: 99%

Stabilization of emulsion polymerization by block and graft copolymers with polysiloxane and poly[(acetylimino)ethylene] sequences

Simionescu¹,

David

Alupei

et al. 1998

Angew. Makromol. Chem.

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SUMMARY: Amphiphilic block and graft copolymers with polysiloxane and poly[(acetylimino)ethylene] sequences were used as nonionic surfactants in the emulsion polymerization of some vinyl monomers (styrene, methyl methacrylate, butyl methacrylate). The peculiarities of the systems (polymerization kinetics and emulsion characteristics) were related to the structural features of the studied emulsifiers and suggested their ability to participate in initiation and transfer reactions and respectively clouding phenomena in aqueous phase.ZUSAMMENFASSUNG: Block-und Pfropfcopolymere mit Polysiloxan-und Poly(acetyliminoethylen)-Bestandteilen wurden als nichtionische Emulgatoren bei der Emulsionspolymerisation von einigen Vinylmonomeren (Styrol, Methylmethacrylat, Butylmethacrylat) benutzt. Die Polymerisationssysteme (kinetische Aussagen, Teilchengröße, Teilchengrößenverteilungen, usw.) wurden charakterisiert und die Emulgatorstruktur-Polymerisationseigenschaft-Beziehungen wurden untersucht. Die Teilnahme der Copolymeren an der Initiierungs-und Ü bertragungsreaktion wurde festgestellt.

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