Narrowly distributed polyethylene-b-poly(ethylene oxide) diblock copolymers (PE-b-PEO) with a linear PE block were successfully synthesized by combination of click coupling reaction of azido-terminated polyethylene (PE−N3) and alkynyl-terminated poly(ethylene oxide) (PEO−CONHCH2CCH). PE−N3 derived from tosylation and subsequent substitution by sodium azide of hydroxyl-terminated PE (PE−OH) which was prepared by means of chain shuttling ethylene polymerization with 2,6-bis[1-(2,6- dimethylphenyl)imino ethyl] pyridine iron (II) dichloride (complex 1)/methylaluminoxane (MAO)/diethyl zinc (ZnEt2) and subsequent in situ oxidation with oxygen. PEO−CONHCH2CCH was synthesized through esterification the hydroxyl end-group on hydroxyl-terminated PEO (PEO−OH) with phosgene and subsequent amidation by propargyl amine. The self-assembly of three double-crystalline PE-b-PEO samples with different block length in water were investigated by laser light scattering (LLS) and transmission electron microscopy (TEM). It was found that, in water, a solvent selectively good for the PEO block, PE-b-PEO chains with proper PE block length could form spherical multicores micelles with the insoluble and crystallized PE blocks as the multicores and the soluble and swollen PEO blocks as the shell. These multicores in one micelle could reaggregate to a single-core as temperature increased. Differential scanning calorimetry (DSC) experiments showed that the crystallization of both PE and PEO blocks was intensely confined by the previously self-assembled structure of PE-b-PEO in aqueous solution.

We report on the synthesis and self-assembly in water of well-defined amphiphilic star-block copolymers with a linear crystalline polyethylene (PE) segment and two or three poly(ethylene glycol) (PEG) segments as the building blocks. Initially, alkynyl-terminated PE (PE-B) is synthesized via esterification of pentynoic acid with hydroxyl-terminated PE, which is prepared using chain shuttling ethylene polymerization with 2,6-bis[1-(2,6-dimethylphenyl) imino ethyl] pyridine iron (II) dichloride/methylaluminoxane/diethyl zinc and subsequent in situ oxidation with oxygen. Then diazido-and triazido-terminated PE (PE-(N 3 ) 2 and PE-(N 3 ) 3 ) are obtained by the click reactions between PE-B and coupling agents containing triazido or tetraazido, respectively. Finally, the three-arm and four-arm star-block copolymers, PE-b-(PEG) 2 and PE-b-(PEG) 3 , are prepared by click reactions between PE-(N 3 ) 2 or PE-(N 3 ) 3 and alkynyl-terminated PEG. The self-assembly of the resultant amphiphilic star-block copolymers in water was investigated by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. It is found that, in water, a solvent selectively good for PEG blocks; these star-block copolymer chains could self-assemble to form platelet-like micelles with insoluble PE blocks as crystalline core and soluble PEG blocks as shell. The confined crystallization of PE blocks in self-assembled structure formed in aqueous solution is investigated by differential scanning calorimetry.

In this paper, under various constraints, based on LR series engine of automobile mixed model assembly line as an example, application of MMALB theory design automobile engine assembly line. To solve the multi-objective optimization problem, we establish the mathematical model between the workstation and workstation internal load balancing two optimization objectives. And engine assembly line is dynamic simulated by using the simulation software eM-Plant. The results verify the validity and practicability of the digital simulation. Finally, the planning scheme guarantees the whole assembly line load balancing and achieves production requirements.