Monitoring the chemical heterogeneity of metallocenecatalysed copolymers of ethylene and higher 1-olefins using CRYSTAF and SEC-FTIR

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Sven M. Graef ◽  
Robert Brüll ◽  
Harald Pasch ◽  
Udo M. Wahner
Keyword(s):  
Differential Scanning Calorimetry ◽  
Size Exclusion Chromatography ◽  
Catalyst System ◽  
Size Exclusion ◽  
Side Chain ◽  
Chemical Heterogeneity ◽  
Scanning Calorimetry ◽  
Crystallisation Temperature ◽  
Exclusion Chromatography

Abstract Copolymers of ethylene with 1-decene, 1-tetradecene and 1-octadecene were prepared using the catalyst system racEt[Ind]2ZrCl2/MAO and were analysed with regard to chemical heterogeneity using crystallisation analysis fractionation (CRYSTAF), differential scanning calorimetry (DSC) and size exclusion chromatography coupled to FTIR (SEC-FTIR). The melting and crystallisation temperatures from DSC decrease linearly with increasing amount of comonomer, independently of the nature thereof. The decrease in crystallisation temperature from CRYSTAF of copolymers with higher 1-olefin content indicates a small dependence on the length of the side chain. The chemical heterogeneity of the copolymers as analysed by DSC and CRYSTAF broadens with increasing comonomer concentration.

Polymerization of 1,3-butadiene with neodymium chloride tripentanolate/triisobutylaluminum binary catalyst system: effect of aging time and reaction temperature

2015 ◽  
Vol 35 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Francisco Javier Enríquez-Medrano ◽  
Luis Alexandro Valencia López ◽  
Yair Agustín de Santiago-Rodríguez ◽  
Florentino Soriano Corral ◽  
Hened Saade Caballero ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Aging Time ◽  
Reaction Temperature ◽  
Catalyst System ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
System Effect ◽  
Neodymium Chloride ◽  
Exclusion Chromatography ◽  
Binary Catalyst

Abstract 1,3-Butadiene monomer was polymerized at 40°C and 60°C by means of a catalyst comprising neodymium (Nd) chloride/1-pentanolate/triisobutylaluminum (TIBA) in cyclohexane as solvent; the catalyst system was aged at 5 and 30 min. The effects on conversion, catalytic activity and polymer final properties were evaluated. The obtained polybutadienes (PBs) were characterized by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) techniques and the results were discussed in terms of the effect of aging time and reaction temperature.

scholarly journals Αυτοοργάνωση αμφίφιλων συμπολυμερών σε εκλεκτικούς διαλύτες

2017 ◽  
Author(s):  
Μαργαρίτα Δρούλια
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Radical Polymerization ◽  
Size Exclusion Chromatography ◽  
1H Nmr ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Exclusion Chromatography ◽  
Nuclear Magnetic

Στην παρούσα Διδακτορική διατριβή συντέθηκαν επιτυχώς δισυσταδικά συμπολυμερή πολυαιθυλενοξειδίου-b-πολυ(μεθακρυλικού φερροκενυλοκαρβοξυ-2-αιθυλεστέρα) (PEO-b-PMAEFc), δισυσταδικά συμπολυμερή πολυαιθυλενοξειδίου-b-πολυ(μεθακρυλικού βενζυλεστέρα) (PEO-b-PBnMA) και τέλος τρισυσταδικά συμπολυμερή πολυ(μεθακρυλικού βενζυλεστέρα)-b-πολυαιθυλενοξειδίου-b-πολυ(μεθακρυλικού βενζυλεστέρα) (PBnMA-b-PEO-b- PBnMA) μέσω ριζικού πολυμερισμού μεταφοράς ατόμου (Atom Tranfer Radical Polymerization, ATRP).Τα παραπάνω συμπολυμερή χαρακτηρίστηκαν με Χρωματογραφία Αποκλεισμού Μεγεθών (Size Exclusion Chromatography, SEC) και Φασματοσκοπία Πυρηνικού Μαγνητικού Συντονισμού (Nuclear Magnetic Resonanse, 1H-NMR). Έτσι προσδιορίστηκαν τα μέσα μοριακά βάρη, η κατανομή των μοριακών βαρών και η σύσταση των συμπολυμερών. Μέσω της Θερμοσταθμικής Ανάλυσης (Thermogravimetric Analysis, TGA) και της Διαφορικής θερμιδομετρίας Σάρωσης (Differential Scanning Calorimetry, DSC) μελετήθηκε η θερμική τους αποικοδόμηση και προσδιορίστηκαν οι θερμοκρασίες υαλώδους μετάπτωσης και οι θερμοκρασίες τήξης των δισυσταδικών και τρισυσταδικών συμπολυμερών σε σχέση με τα αντίστοιχα ομοπολυμερή. Τέλος μελετήθηκε η αυτοοργάνωση των παραπάνω συμπολυμερών σε εκλεκτικούς διαλύτες (νερό και ακετονιτρίλιο) ως προς τη μια συστάδα (πολυαιθυλενοξείδιο) μέσω της δυναμικής σκέδασης φωτός και επιβεβαιώθηκε ο σχηματισμός μικκυλίων και μικκυλιακών συσσωματωμάτων. Ακολούθως προσδιορίστηκε η υδροδυναμική ακτίνα και ο συντελεστής άπειρης αραιώσης των παραπάνω μικκυλιακών δομών.

On the feasibility of determining polymer chemical heterogeneity by SEC with continuous off-line Raman detection

2015 ◽  
Vol 6 (27) ◽  
pp. 4864-4874 ◽  
Author(s):  
Leena Pitkänen ◽  
Aaron A. Urbas ◽  
André M. Striegel
Keyword(s):  
Raman Spectroscopy ◽  
Size Exclusion Chromatography ◽  
Detection Method ◽  
Size Exclusion ◽  
Chemical Heterogeneity ◽  
Exclusion Chromatography

Examined here is the feasibility of employing Raman spectroscopy as a detection method in size-exclusion chromatography (SEC) and related macromolecular separations, for the purposes of determining the chemical heterogeneity of copolymers.

Combined Main- and Side-Chain Azobenzene Polyesters: A Potential For Photoinduced Nonlinear Waveguides

1999 ◽  
Vol 561 ◽  
Author(s):  
F. Sahlén ◽  
T. Geisler ◽  
S. Hvilsted ◽  
N. C. R. Holme ◽  
P. S. Ramanujam ◽  
...  
Keyword(s):  
Refractive Index ◽  
Third Harmonic Generation ◽  
Size Exclusion ◽  
Side Chain ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Nonlinear Waveguides ◽  
Third Harmonic ◽  
Exclusion Chromatography ◽  
Uv Visible

ABSTRACTNew combined main- and side-chain azobenzene polyesters, which exhibit an intensity dependent refractive index, have been prepared in order to optically fabricate nonlinear waveguides. Novel sulfone azobenzenes, a diester, (4-[[5-(ethoxycarbonyl)pentyl]sulfonyl]-4'-[[5-(ethoxycarbonyl)pentyl]methylamino] azobenzene, and a diol, 4-[[(8-hydroxy-7-methylhydroxy)-octyl]sulfonyl]-4'-N, N-dimethylamino azobenzene, have been used to prepare new polyesters by transesterification in the molten state. The polyesters have been characterized by UV-visible spectroscopy, differential scanning calorimetry (DSC), size exclusion chromatography (SEC), third harmonic generation (THG) and optical anisotropy measurements. The molar masses of the polyesters were in the range of 5000-10000 g mol−1, which was sufficient in order to spin coat thin films. From THG measurements the polymers are shown to possess an offresonance electronic X(3) of the order 10−12 esu corresponding to a nonlinear refractive index of 2.3×10−14 cm2/W.

Synthesis and properties of a spinnable phase change material CDA-IPDI-MPEG

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Shiliang Cheng ◽  
Yanmo Chen ◽  
Hao Yu ◽  
Meifang Zhu
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Catalyst System ◽  
Molecular Structures ◽  
Size Exclusion ◽  
Dibutyltin Dilaurate ◽  
Reaction Products ◽  
Scanning Calorimetry ◽  
Exclusion Chromatography ◽  
Change Material

AbstractA comb like phase change material (PCM) CDA-IPDI-MPEG, based on cellulose diacetate (CDA) as a backbone, with methoxy polyethylene glycol (MPEG) grafted onto it, was synthesized by a two-step reaction in the presence of dibutyltin dilaurate (DBTDL) catalyst system, using acetone as solvent and isophorone diisocyanate (IPDI) as crosslinking reagent. Size exclusion chromatography (SEC) was used to characterize the molecular weight distribution of each step reaction products. Back titration was utilized for determination of free isocyanate. The molecular structures were confirmed qualitatively using FTIR and H1-NMR measurements. Phase change properties were characterized by differential scanning calorimetry (DSC).

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