Results 31 to 40 of about 651 (134)

Caracterização de polietilenos lineares de baixa densidade I.: determinação do teor de ramificação por métodos espectroscópicos Linear low density polyethylene characterization - I.: spectroscopic methods for comonomer content determination

Polímeros, 2005
Os polietilenos lineares de baixa densidade (LLDPE) apresentam propriedades variando amplamente em função da concentração e do tipo de comonômero utilizado na copolimerização, além do tipo de catalisador.
Antonio C. Quental, Lilian S. Hanamoto, Maria I. Felisberti   +2 more
doaj   +1 more source

Potential of Thermoset Polyolefins for FRP Concrete Reinforcing Bars

Polymer Composites, EarlyView.
Overview of XLPO and pDCPD resins for FRP reinforcing bars, highlighting resin chemistry, key performance characteristics, fiber sizing interactions, and principal degradation mechanisms in concrete environments. ABSTRACT Although thermoset polyolefins offer resistance to hydrolytic degradation and favorable processing characteristics, their potential ...
Osama Omar, Farzaneh Mahmoudi, Leonidas G. Bachas, Francisco De Caso, Brahim Benmokrane, Antonio Nanni   +5 more
wiley   +1 more source

Oxidative Stability and Rheological Features in Recycled Composites Based on Postconsumer Polypropylene and Antioxidant‐Loaded Silicas

Polymer Engineering &Science, EarlyView.
Role of antioxidant supported on MCM‐41 and nano‐silica in enhancing oxidation induction time (OIT) and nucleation performance. ABSTRACT Plastic recycling efforts are hindered by the reduction of material properties in recyclates stemming from oxidative degradation of their polymeric chains.
Enrique Blázquez‐Blázquez, Kalman B. Migler, Tamara Díez‐Rodríguez, María L. Cerrada, Ernesto Pérez   +4 more
wiley   +1 more source

Speciation, Structural Refinement, and Distribution of Ti Sites in Titanium Silicalite‐1 From 47/49Ti NMR Crystallography at 28.2 Tesla

Angewandte Chemie, Volume 138, Issue 15, 6 April 2026.
Titanium silicalite‐1 (TS‐1), used in industrial selective oxidation processes, depends on specific, yet still unresolved Ti sites, dispersed within the framework of an MFI‐zeolite. Applying high field (28.2 T) 47/49Ti NMR and 17O NMR spectroscopy for an array of TS‐1 catalysts enables the development of an NMR crystallography protocol and the ...
Christoph J. Kaul, Jonas Koppe, Lukas Lätsch, Michael Wörle, Sadig Aghazada, Jacob B. Holmes, Christina Wartmann, Mingji Zheng, Albrecht Berkessel, Trees De Baerdemaeker, Andrei‐Nicolae Parvulescu, Karsten Seidel, J. Henrique Teles, Alexander V. Yakimov, Christophe Copéret   +14 more
wiley   +2 more sources

Facile Approach to Modulating Stereochemistry in Ring‐Opening Metathesis Polymerization of Cyclooctadiene

Journal of Polymer Science, EarlyView.
The stereochemistry of polybutadiene made by ring‐opening metathesis polymerization (ROMP) evolves both during and after polymerization, as secondary metathesis shifts cis‐rich kinetic products toward trans‐rich equilibrium compositions. By tuning catalyst identity, additives, temperature, and reaction time, polybutadienes with 28%–80% trans content ...
Amira S. Eldin, Michael D. Schulz
wiley   +1 more source

From Cages to Sheets: Computational Elucidation of Methylaluminoxane Structure and Reactivity

ChemPlusChem, Volume 91, Issue 8, August 2026.
Methylaluminoxane (MAO), the dominant cocatalyst in metallocene‐based olefin polymerization, has resisted structural characterization for decades. This review traces the computational journey from early cage and nanotube proposals to the identification of two‐dimensional aluminoxane sheets as the thermodynamically preferred motif, and how this ...
Mikko Linnolahti, Perttu Hanhisalo, Aleksi Vähäkangas   +2 more
wiley   +1 more source

"Supported Ziegler-Natta catalysts from MgCl2·nROH precursors and its catalytic behaviors for diene copolymerization"

Hecheng xiangjiao gongye
The precursor MgCl2 · nROH of supported Ziegler Natta catalyst was prepared by chemical activation method, and different pre catalysts TiCl4/MgCl2 (C-Cat) were prepared by loading TiCl4.
FAN Xun-zhang, ZHAO Yuan-jin, LUO Shu-fang, HE Ai-hua?
doaj   +1 more source

Nano-Dispersed Ziegler-Natta Catalysts for 1 μm-Sized Ultra-High Molecular Weight Polyethylene Particles

Frontiers in Chemistry, 2018
A catalytic approach to synthesize microfine ultra-high molecular weight polyethylene (UHMWPE) particles was proposed based on the exploitation of nano-sized catalysts.
Patchanee Chammingkwan, Yusuke Bando, Minoru Terano, Toshiaki Taniike   +3 more
doaj   +1 more source

Production of titanium tetrachloride (TiCl4) from titanium ores: A review [PDF]

Polyolefins Journal, 2017
Titanium (Ti) is the ninth most abundant element on earth. The titanium mineral ores are widely distributed in different parts of the world. The two main ores of titanium include rutile (TiO2) and ilmenite (FeO.TiO2).
Hossein Bordbar, Ali Akbar Yousefi, Hossein Abedini   +2 more
doaj   +1 more source

Acyclic Hydrocarbon α,ω‐Dienes: From Biomass and Plastic Upcycling to Carbocycles, Precision Polymers, and Cross‐Linked Elastomers

ChemSusChem, Volume 19, Issue 14, 29 July 2026.
Hydrocarbon α,ω‐dienes are mainly produced from steam‐cracking derivatives, but high costs, complexity, and environmental impact limit their use. This review highlights sustainable paths from biomass and plastic upcycling, and surveys catalytic transformations into carbocycles and specialty polymers, emphasizing their role as modular building blocks ...
Rosa Villaccio, Giuseppe Leone
wiley   +1 more source