Housmans, JW Jan-Willem

Meijer, HEH

Peters, GWM Gerrit

Housmans, J.W.

Peters, G.W.M.

Meijer, H.E.H.

Pure OAI Repository

 Flow-induced crystallization of PP/PE copolymersCitation for published version (APA):Housmans, J. W., Peters, G. W. M., & Meijer, H. E. H. (2005). Flow-induced crystallization of PP/PE copolymers.Poster session presented at Mate Poster Award 2005 : 10th Annual Poster Contest.Document status and date:Published: 01/01/2005Document Version:Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can beimportant differences between the submitted version and the official published version of record. Peopleinterested in the research are advised to contact the author for the final version of the publication, or visit theDOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and pagenumbers.Link to publicationGeneral rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            • Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            • You may not further distribute the material or use it for any profit-making activity or commercial gain            • You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, pleasefollow below link for the End User Agreement:www.tue.nl/taverneTake down policyIf you believe that this document breaches copyright please contact us at:openaccess@tue.nlproviding details and we will investigate your claim.Download date: 16. Nov. 202312/department of mechanical engineering PO Box 513, 5600 MB Eindhoven, the NetherlandsFlow-induced crystallization of PP/PE copolymers.J.W. Housmans, G.W.M. Peters, H.E.H. MeijerEindhoven University of Technology, Department of Mechanical EngineeringIntroductionThe major disadvantages of PP are low temperature brittle-ness and opacity. A way to improve these properties is to usePP/PE random copolymers (RACO’s) that also have the advan-tage of a decrease of the processing temperatures [1]. Thisstudy deals with the influence of ethylene content on crystal-lization behavior and the characterization of these materialsfor future modeling purposes.Materials and methods2 A PP homopolymer and three PP/PE RACO’s with differ-ent ethylene contents (Borealis, Linz).2 All grades have the same molar mass (Mw ∼ 310kg/mol) and polydispersity (D ∼ 3.4) [2].2 Oscillatory experiments to determine the linear vis-coelastic response.2 Short term shear experiments, see Fig. 1.Tγ̇tT = 230◦CT = Tc,exppre-shearMelt material at 230◦CCool to Tc,expUndercooling: Tm − Tc,exp=18◦CApply pre-shear:γ̇ = 30s−1, tflow = 3sFollow crystallization process:G’ in timeFigure 1 Short-term shear experiment.ResultsThe introduction of ethylene monomer in PP leads to:2 a decrease in crystallinity.2 a depression of the glass-transition (Tg), melt (Tm) andcrystallization temperature (Tc, Table 1).Table 1: Basic characteristics of the PP grades.Type Ethylene Tg Tm Tc Xc[mol%] 1) [◦C] 2) [◦C] 2) [◦C] 2) [%] 2,3)HD234CF 0 -2 163 112 45RD204CF 3.4 -4 147 105 39RD226CF 5.2 -5 143 101 37RD208CF 7.3 -11 138 95 331) From [2], determined using NMR spectroscopy.2) Determined using DSC, Ṫ = 10◦C/min3)∆Hm = 209 J/g for 100% crystalline PP, [2].10-210-1100101102103100101102103104105w [rad/s]G' [Pa], G" [Pa],h* [Pa s]10-210-1100101102103100101102103104105w [rad/s]G' [Pa], G" [Pa],h* [Pa s]Figure 2 Linear viscoelastic response of HD234CF (left) and RD208CF(right), measured at different temperatures and shifted to Tref =220◦C. ◦ = G’, ⋄ = G”,△ = η∗.Although a clear influence of ethylene is seen on e.g. Tm, thelinear viscoelastic behavior is not altered (Fig. 2).100101102103104105103104105106107108Time [s]G' [Pa]QuiescentPre-sheart1/2= 2.2*104[s]t1/2= 4.7*103[s]100101102103104105103104105106107108Time [s]G' [Pa]QuiescentPre-sheart1/2= 3.5*103[s]t1/2= 1.3*103[s]Figure 3 Crystallization behavior for HD234CF (left) and RD208CF(right). Red = without flow, blue = with flow (pre-shear: γ̇ =30s−1, tflow = 3s), ◦: defines t 12.ConclusionsAs known from earlier studies [3], the crystallization processis accelerated when shear is applied, Fig. 3 (left). Crystalliza-tion of PP is also greatly influenced by the addition of ethy-lene when compared at the same undercooling, i.e. the half-time of crystallization (t 12) is decreased with almost 1 orderof magnitude, Fig. 3.Future workA rheological classification of flow induced crystallization isproposed, which identifies different flow regimes [4]. Thecharacteristics can be summarized in a plot (tflow, t 12), seeFig. 4 [5]. How this graph is influenced by the addition ofethylene will be the subject of future research.t 12tflowT = const.Quiescentγ̇I γ̇τrep<1, γ̇τR<1IIγ̇τrep>1,γ̇τR<1IIIγ̇τrep>1, γ̇τR>1Figure 4 Rheological classification of flow induced crystallization.References:[1] LAIHONEN, S. ET AL.: Polymer (1997) 38, 371[2] GAHLEITNER, M. ET AL.: J. Appl. Pol. Sci. (2003) 95, 1073[3] VLEESHOUWERS, S. AND MEIJER H.E.H.: Rheologica Acta (1996) 35, 391[4] VAN MEERVELD, J. ET AL.: Rheologica Acta (2004) 44, 119[5] VEGA, J.F.. ET AL.: in preparation (2005)

English

Flow-induced crystallization of PP/PE copolymers

NARCIS 

Repository TU/e

Flow-induced crystallization of PP/PE copolymers

Abstract

Similar works

Full text

Available Versions

Pure OAI Repository

NARCIS

Repository TU/e