The nucleation effect of linear polyethylene lamellae over the crystallization of branched polyethylene

1996 ◽  
Vol 36 (3) ◽  
pp. 361-367 ◽  
Author(s):  
C. C. Puig
Keyword(s):  
Linear Polyethylene ◽  
Branched Polyethylene ◽  
Nucleation Effect

Mechanistic study of the competitiveness between branched and linear polyethylene production on N-arylcyano-β-diketiminate nickel hydride

2020 ◽  
Vol 11 (41) ◽  
pp. 6640-6649
Author(s):  
Daniela E. Ortega ◽  
Diego Cortés-Arriagada ◽  
Oleksandra S. Trofymchuk ◽  
Fabiane M. Nachtigall ◽  
Leonardo S. Santos ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Mechanistic Study ◽  
Linear Polyethylene ◽  
Branched Polyethylene ◽  
Nickel Hydride ◽  
Polyethylene Production

This paper provides a guide to identify and understand the mechanistic origin of the catalytic activity and selectivity in the production of linear and branched polyethylene through a nickel hydride catalyst.

scholarly journals Crystallization Behavior and Mechanical Properties of Poly(ε-caprolactone) Reinforced with Barium Sulfate Submicron Particles

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2368
Author(s):  
Hegoi Amestoy ◽  
Paul Diego ◽  
Emilio Meaurio ◽  
Jone Muñoz ◽  
Jose-Ramon Sarasua
Keyword(s):  
Barium Sulfate ◽  
Thermal Studies ◽  
Polarized Light ◽  
Optical Microscope ◽  
Submicron Particles ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Nucleation Effect ◽  
Crystal Fraction ◽  
Light Optical Microscope

Poly(ε-caprolactone) (PCL) was mixed with submicron particles of barium sulfate to obtain biodegradable radiopaque composites. X-ray images comparing with aluminum samples show that 15 wt.% barium sulfate (BaSO4) is sufficient to present radiopacity. Thermal studies by differential scanning calorimetry (DSC) show a statistically significant increase in PCL degree of crystallinity from 46% to 52% for 25 wt.% BaSO4. Non-isothermal crystallization tests were performed at different cooling rates to evaluate crystallization kinetics. The nucleation effect of BaSO4 was found to change the morphology and quantity of the primary crystals of PCL, which was also corroborated by the use of a polarized light optical microscope (PLOM). These results fit well with Avrami–Ozawa–Jeziorny model and show a secondary crystallization that contributes to an increase in crystal fraction with internal structure reorganization. The addition of barium sulfate particles in composite formulations with PCL improves stiffness but not strength for all compositions due to possible cavitation effects induced by debonding of reinforcement interphase.

scholarly journals A High-Strain-Rate Superplasticity of the Al-Mg-Si-Zr-Sc Alloy with Ni Addition

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2028
Author(s):  
Andrey Mochugovskiy ◽  
Anton Kotov ◽  
Majid Esmaeili Ghayoumabadi ◽  
Olga Yakovtseva ◽  
Anastasia Mikhaylovskaya
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Strain Rate Range ◽  
Zener Pinning ◽  
Nucleation Effect ◽  
Pinning Effect ◽  
Ni Addition ◽  
Elongation To Failure ◽  
Mean Size ◽  
High Temperature Tensile

The current study analyzed the effect of Ni content on the microstructure and superplastic deformation behavior of the Al-Mg-Si-Cu-based alloy doped with small additions of Sc and Zr. The superplasticity was observed in the studied alloys due to a bimodal particle size distribution. The coarse particles of eutectic origin Al3Ni and Mg2Si phases with a total volume fraction of 4.0–8.0% and a mean size of 1.4–1.6 µm provided the particles with a stimulated nucleation effect. The L12– structured nanoscale dispersoids of Sc- and Zr-bearing phase inhibited recrystallization and grain growth due to a strong Zener pinning effect. The positive effect of Ni on the superplasticity was revealed and confirmed by a high-temperature tensile test in a wide strain rate and temperature limits. In the alloy with 4 wt.% Ni, the elongation-to-failure of 350–520% was observed at 460 °C, in a strain rate range of 2 × 10−3–5 × 10−2 s−1.

The chloro‐substituent enhances performance of 2,4‐bis (imino)pyridylchromium catalysts yielding highly linear polyethylene

2020 ◽  
Vol 34 (4) ◽  
Author(s):  
Badral Gansukh ◽  
Qiuyue Zhang ◽  
Zygmunt Flisak ◽  
Tongling Liang ◽  
Yanping Ma ◽  
...  
Keyword(s):  
Linear Polyethylene
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