Effect of polymerization temperature on the microtacticity of isotactic poly(propylene) prepared using heterogeneous (MgCl2-supported) Ziegler-Natta catalysts

1998 ◽  
Vol 199 (9) ◽  
pp. 1873-1878 ◽  
Author(s):  
John C. Chadwick ◽  
Giampiero Morini ◽  
Giulio Balbontin ◽  
Olof Sudmeijer
Keyword(s):  
Polymerization Temperature ◽  
Poly Propylene ◽  
Ziegler Natta Catalysts

Solid-State NMR Characterization of the Chemical Defects and Physical Disorders in α Form of Isotactic Poly(propylene) Synthesized by Ziegler–Natta Catalysts

2013 ◽  
Vol 46 (16) ◽  
pp. 6507-6519 ◽  
Author(s):  
Zhen Li ◽  
Toshikazu Miyoshi ◽  
Mani K. Sen ◽  
Tadanori Koga ◽  
Akihiro Otsubo ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Characterization ◽  
Physical Disorders ◽  
Poly Propylene ◽  
Ziegler Natta Catalysts

scholarly journals Effect of Polymerization Conditions on Thermal and Mechanical Properties of Ethylene/1-Butene Copolymer Made with Ziegler-Natta Catalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mostafizur Rahaman ◽  
M. Anwar Parvez ◽  
J. B. P. Soares ◽  
I. A. Hussein
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Yield Stress ◽  
Hydrogen Pressure ◽  
Polymerization Reaction ◽  
Polymerization Temperature ◽  
Thermal And Mechanical Properties ◽  
Ethylene Pressure ◽  
Polymerization Conditions ◽  
Ziegler Natta Catalysts

The effect of polymerization conditions on thermal and mechanical properties of ethylene/1-butene copolymers synthesized through titanium-magnesium-supported Ziegler-Natta catalysts was studied. The increase in hydrogen pressure leads to a decrease in molecular weight (MW), storage modulus, and melting temperature. However, it yields an increase in molecular weight distribution (MWD),tan⁡δ, % crystallinity, tensile modulus, yield stress, and strain at break. The effects of ethylene pressure and polymerization temperature on the copolymer MW, MWD and thermal and mechanical properties have been investigated. However, the impacts of ethylene pressure and polymerization temperature on copolymer modulus, tensile strength, % crystallinity, crystallization peak temperature, yield stress, strain at break, and yield strain are marginal. The hydrogen pressure plays a major role in controlling the copolymer properties because it acts as an efficient chain transfer agent during polymerization reaction. The MW is the key parameter that influences flow activation energy. However, the other mechanical, dynamic mechanical, and thermal properties not only depend on MW but are also influenced by other parameters.

Molecular dynamics of poly(propylene) glycol in nanometer confinements

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-271-Pr7-274 ◽  
Author(s):  
A. Schönhals ◽  
H. Goering ◽  
K.-W. Brzezinka ◽  
Ch. Schick
Keyword(s):  
Molecular Dynamics ◽  
Propylene Glycol ◽  
Poly Propylene

Effect of Polymerization Temperature on Polymerization Degree and Structure of Calcium Polyphosphate

2012 ◽  
Vol 27 (2) ◽  
pp. 174-178
Author(s):  
Hang WU ◽  
Li-Fang ZHANG ◽  
Wei BAI ◽  
Chi MA ◽  
Cheng-Dong XIONG
Keyword(s):  
Polymerization Temperature ◽  
Polymerization Degree ◽  
Calcium Polyphosphate

Crystallization of Isotactic Poly(propylene) in Solution as Followed by Slow Calorimetry

1995 ◽  
Vol 60 (11) ◽  
pp. 1905-1924 ◽  
Author(s):  
Hong Phuong-Nguyen ◽  
Geneviève Delmas
Keyword(s):  
Molecular Weight ◽  
Crystal Growth ◽  
High Temperature ◽  
Heat Of Fusion ◽  
Complete Dissolution ◽  
Polymer Molecular Weight ◽  
Solvent Quality ◽  
Temperature Ramp ◽  
Poly Propylene

Dissolution, crystallization and second dissolution traces of isotactic poly(propylene) have been obtained in a slow temperature ramp (3 K h-1) with the C80 Setaram calorimeter. Traces of phase-change, in presence of solvent, are comparable to traces without solvent. The change of enthalpy on heating or cooling, ∆Htotal, over the 40-170 °C temperature range, is the sum of two contributions, ∆HDSC and ∆Hnetwork. The change ∆HDSC is the usual heat obtained in a fast temperature ramp and ∆Hnetwork is associated with a physical network whose disordering is slow and subject to superheating due to strain. When dissolution is complete, ∆Htotal is equal to ∆H0, the heat of fusion of perfect crystals. The values of ∆Htota for nascent and recrystallized samples are compared. Dissolution is the tool to evaluate the quality of the crystals. The repartition of ∆Htotal, into the two endotherms, reflects the quality of crystals. The crystals grown more rapidly have a higher fraction of network crystals which are stable at high T in the solvents. A complete dissolution, i.e. a high temperature (170 °C or more) is necessary to obtain good crystals. The effect of concentration, polymer molecular weight and solvent quality on crystal growth is analyzed.

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