Macromolecular Reaction Engineering
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Materials Science Weekly Newsletter
Recently Published Articles
- Some Factors Affecting the Molecular Weight Distribution (MWD) in Low Density Polyethylene Multizone Autoclave Polymerization Reactors
Enrique Saldívar-Guerra, Almendra Ordaz-Quintero, Ramiro Infante-Martínez, Jorge Herrera-Ordóñez, Luis Villarreal-Cárdenas, Diana Ramírez-Wong, Evelia Rivera-Rodríguez, Rodolfo Flores-Flores and Luis Miramontes-Vidal
Article first published online: 21 JUL 2015 | DOI: 10.1002/mren.201500030
This paper discusses the effect of several factors, including the pressure and temperature conditions used in the reactor, on the MWD, which is one of the main features of LDPE. Simulations with the Polyred software package provide a set of kinetic parameters that reproduce, using realistic conditions, the observed trends in number average molecular weight and MWD dispersity in the commercial multizone autoclave reactor.
- Challenges and Opportunities in Continuous Production of Emulsion Polymers: a Review
José M. Asua
Article first published online: 14 JUL 2015 | DOI: 10.1002/mren.201500032
Profit margin reduction and global competition are pushing emulsion polymer producers to consider process intensification that mainly relies on the replacement of semicontinuous reactors by continuous ones. In this work, the challenges in the continuous production of emulsion polymers are discussed and ways in which the challenges can be transformed in opportunities are reviewed.
- Continuous Tanks-in-Series Process for Free-Radical Polymerization with Long-Chain Branching and Scission: Effect of the Order of a Large Tank
Article first published online: 7 JUL 2015 | DOI: 10.1002/mren.201500031
Tanks-in-series model for free-radical polymerization that involves simultaneous long-chain branching and scission is generalized to investigate the effect of the sequence number n of a big reactor, finding that the largest weight-average MW is obtained for n = 1. The full distributions of MW, the branching density and the radii of gyration are investigated to propose a novel reactor design strategy.
- Growth of Polyethylene Nanofibrils Over rac-Et(Indenyl)2ZrCl2/MAO Catalyst Supported on Silica Nanotubes
Sang Yool Lee, Joong Jin Han, Sang Bok Lee and Kyu Yong Choi
Article first published online: 6 JUL 2015 | DOI: 10.1002/mren.201500022
Silica nanotubes deposited with a metallocene catalyst polymerize ethylene to nanofibrils that extrude out from the nanoscale channels as intertwined bundles. This work shows that the basic dimension of polyethylene nanofibrils at the catalyst surface is 30–35 nm diameter fibrils of high crystallinity. The catalytic silica nanotubes also offer good accessibility for monomer and hence high initial polymerization rate.
- Poly(3-hydroxybutirate-co-3-hydroxyvalerate)–Polystyrene Hybrid Nanoparticles via Miniemulsion Polymerization
Fernanda Vitória Leimann, Cristiane Costa, Odinei Hess Gonçalves, Anna Musyanovych, Katharina Landfester, Claudia Sayer and Pedro Henrique Hermes de Araújo
Article first published online: 6 JUL 2015 | DOI: 10.1002/mren.201500023
In the present work, a novel hybrid polymer is synthesized with PHBV and PS by miniemulsion polymerization. Nanoparticles presenting narrow size distribution, a high grafting yield, and the hybrid formation is confirmed by FTIR and DSC. The new material presents different thermal characteristics enabling its use for new applications.