Oxidative Stress and Neurodegeneration

End-to-End High-Throughput Approach for Data-Driven Internal Donor Development in Heterogeneous Ziegler–Natta Propylene Polymerization

“…The overall data set in Table , which is unprecedented when considering the size and internal consistency, highlights a fascinating and intriguing mix of predictable and surprising QSPRs. The negative correlation between Ti and ID contents (Figure S2a) can be understood as a result of the competitive adsorption of TiCl 4 and ID on the coordinatively unsaturated MgCl 2 surfaces. ,,,, IDs resulting into high Ti contents included those prone to secondary reactions (that is, tautomerization for KE and DK; esterification with Ti-OEt for AN; transesterification with Ti-OEt for isopropyl DE) and oxalates (L0-DE#) that hardly adsorbed on MgCl 2 . In line with common sense, this indicates that Lewis bases acting effectively as IDs are chemically stable/inert and have high affinity for MgCl 2 . Catalysts with high Ti content (i.e., low ID content) produced PP with comparatively low stereoregularity, as indicated consistently by the relevant polymer features, namely, I.I., T el (Figure S2b), mmrrmm , and rrrrrr . OEt groups left over from Mg­(OEt) 2 in the catalyst have a detrimental impact on activity and stereoselectivity (Figure S2c and previous literature). , Residual OEt amount turned out to depend significantly on ID molecular structure: it was lower in general with diester IDs (and especially so with oxalates) than with all other ID classes. Pore volume turned out to be highly sensitive to ID molecular structure: while an overall trend was hard to discern, specific phthalates and malonates were found to contribute to the smaller pore volume.…”

“…The negative correlation between Ti and ID contents (Figure S2a) can be understood as a result of the competitive adsorption of TiCl 4 and ID on the coordinatively unsaturated MgCl 2 surfaces. ,,,, IDs resulting into high Ti contents included those prone to secondary reactions (that is, tautomerization for KE and DK; esterification with Ti-OEt for AN; transesterification with Ti-OEt for isopropyl DE) and oxalates (L0-DE#) that hardly adsorbed on MgCl 2 . In line with common sense, this indicates that Lewis bases acting effectively as IDs are chemically stable/inert and have high affinity for MgCl 2 .…”

“…Moving from Natta’s initial invention, heterogeneous Ziegler–Natta (ZN) catalysts have dominated the industrial production of isotactic polypropylene (PP). − The first two generations were combinations of crystalline TiCl 3 in a layered modification, either pure or in mixture with AlCl 3 , and an alkyl-Al compound . That the addition of an organic Lewis base (e.g., an ether) can be beneficial for certain aspects of catalytic performance (like productivity) has been known since the 1960s, but catalyst modification with bases became systematic only from the 1970s, with the so-called high-yield formulations .…”

Simultaneous Promotion of the Mechanical Flexibility and Dielectric Strength of Impact Polypropylene Copolymers Containing Multifold H-Shape Long-Chain-Branching Structures for Recyclable Power Cable Insulation Application

“…Impact polypropylene copolymers (IPCs), i.e., the heterophasic PP copolymers composed of PP homopolymer and ethylene-propylene random copolymer (EP copolymer, EPC) prepared by heterogeneous Ziegler–Natta catalysts in successive propylene homopolymerization–ethylene/propylene copolymerization, fall perfectly in the material category of polyolefin elastomer-modified PP, thus holding great potential for power cable insulation application. ,, As in situ synthesized materials, IPCs are advantaged in the process over other PP/polyolefin elastomer alloys or blends wrought by physical mixing. − Unfortunately, in disadvantage, commercial IPC resins are generally perceived to be neither mechanically nor electrically adequate for such an application, although they are indeed appreciated for good thermo-mechanical properties fulfilling the basic requirement for a thermoplastic polymer to be able to substitute the thermosetting XLPE . On the mechanical aspect, IPC resins are often deemed still short in flexibility, despite the fact that in IPC the hard PP has been replaced in a considerable part by elastic EPC.…”

Reactive Compatibilization of Impact Copolymer Polypropylene and Organically Modified Mesoporous Silica to Prepare Composites Possessing Enhanced Mechanical Properties

“…Polyolefins are known to play a vital role in society, both as commodity thermoplastics in daily activities, as well as for high-performance engineering applications. Polypropylene (PP) is an extremely popular choice, owing to its low cost of production and processing, recyclability, and good balance between useful physical and chemical characteristics . To further extend the versatility of PP, extensive research and development have been done and are still being continued in the preparation of composites.…”