02389nas a2200265   4500008004100000022001400041245006000055210005900115260000800174300001200182490000700194520158300201653001901784653002801803653003301831653002301864653001101887100002701898700002401925700001801949700002401967700001901991700002402010856008902034       2023                        eng d  a1060-132500aEmerging trends in olefin polymerization: a perspective0 aEmerging trends in olefin polymerization a perspective  cNOV  a731-7500 v603 a<p>The seemingly matured field of olefin polymerization still poses several challenges and holds enormous potential to meet contemporary material requirements. In this feature article, we examine the progress of olefin polymerization in the last two decades. Among the several emerging trends, we identify four most impactful discoveries, namely, (i) disentangled ultra-high molecular weight polyethylene (dUHMWPE), (ii) disubstituted functional olefin copolymerization, (iii) incorporation of bioderived comonomers in polyolefins, and (iv) application of above (ii, iii) functional polyolefins as compatibilizers. The dUHMWPE has attracted significant attention and heterogeneous Ziegler-type catalysts, homogenous metallocene, and post-metallocene catalysts have been reported to produce disentangled ultrahigh molecular weight polyethylene. Insertion copolymerization of difunctional disubstituted olefins has been reported only recently and ortho-phosphinobenzene sulfonate palladium catalyst outperforms the other catalysts. Interestingly, insertion copolymerization of bioderived olefins has witnessed a surge in the number of reports. Sugar and plant oil-derived olefins have been copolymerized with ethylene to obtain relatively hydrophilic polyethylene. The functional polyethylene is finding a new application as compatibilizer or displays better adhesion to surfaces. Thus, the feature article offers a succinct account of emerging trends in polyolefins, identifies the most impactful contributions, and debates the application potential of these new materials.</p>
10acompatibilizer10aFunctional polyethylene10aInsertion (co)polymerization10arenewable monomers10auHMWPE1 aBirajdar, Rajkumar, S.1 aBodkhe, Dnyaneshwar1 aGupta, Poonam1 aShaikh, Maulali, H.1 aRamekar, Rohan1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/emerging-trends-olefin-polymerization-perspective02889nas a2200277   4500008004100000022001400041245010900055210006900164260000800233300001100241490000800252520196700260653002002227653002502247653001702272653002302289653001102312100002802323700001702351700002402368700002502392700002202417700002302439700002402462856012502486       2026                        eng d  a0014-305700aSteric-bulk directed polymerization of ethylene to disentangled ultra-high molecular weight polyethylene0 aStericbulk directed polymerization of ethylene to disentangled u  cJUN  a1147620 v2533 a<p>
	{The electron-withdrawing pentafluorophenyl phenoxy-imine-derived titanium complexes are known to produce ultrahigh molecular weight polyethylene (UHMWPE). However, cyclohexyl phenoxy-imine-derived zirconium complexes have been reported to produce low molecular weight polyethylene. The disparity between the two types of polyethylenes and the two types of catalysts can be bridged if a titanium complex bearing sterically bulky groups is made to produce UHMWPE. We report steric bulk-directed cyclohexyl phenoxy-imine titaniumcatalyzed synthesis of UHMWPE in a disentangled state. The influence of steric bulk in a phenoxy-imine-cyclohexyl ligand framework on titanium complex formation and subsequent ethylene polymerization was investigated through a combined computational and experimental approach. Density functional theory (DFT) and buried volume analyses indicated that increasing steric demand from -H to -Me to -tert-Bu substituents enhances the buried volume around the metal center, potentially favoring high molecular weight polyethylene formation. Guided by these insights, three ligands, L1-L3, were synthesized in excellent yields and fully characterized, including by single-crystal X-ray diffraction. Treatment of L1-L3 with a titanium precursor produced respective complexes, Cat.1-Cat.3, in good yields. These were characterized by NMR, IR, MS, and single-crystal X-ray diffraction. Upon activation with various co-catalysts [methyl aluminoxane (MMAO), triisobutylaluminum (TIBA), and tetrakis (pentafluoro phenyl) borate (BT)], these complexes initiated ethylene polymerizations. The catalytic activity increased from Cat.1 to Cat.2 with growing steric bulk, but decreased for the highly hindered Cat.3, likely due to restricted monomer access to the active site. Among the three, Cat.2, in combination with MMAO, showed the best performance under optimized conditions and produced ultrahigh molecular weight polyethylene (UHMWPE</p>
10aMetal catalysis10aPhenoxy-imine ligand10aPolyethylene10aTitanium complexes10auHMWPE1 aBodkhe, Dnyaneshwar, V.1 aPatel, Ketan1 aShaikh, Maulali, H.1 aKaulage, Sandeep, H.1 aMahajan, Digvijay1 aPol, Harshawardhan1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/steric-bulk-directed-polymerization-ethylene-disentangled-ultra-high-molecular-weight