POLYMERIZATION OF ETHYLENE METHYL PHOSPHATE IN THE PRESENCE OF SODIUM POLY(ETHYLENE GLYCOL)ATE

Poly(ethylene methyl phosphate)-poly(ethylene glycol)-poly(ethylene methyl phosphate) triblock copolymers carrying hydroxyl group at both chain ends were synthesized with sodium poly(ethylene glycol)ate as initiator. The effects of the factors such as solvent, amount of the initiator and reaction time were investigated. The copolymers were characterized by IR, H-1-NMR, H-1{P-31}-NMR, C-13-NMR, P-31{H-1}-NMR, and DSC. High molecular weight of the copolymer and high yield of the polymerization were achieved within 3 min at 25 degrees C. The polymerization process was studied by P-31{H-1}-NMR and transesterification was found during longer polymerization time.

Fabrication of telechelic DNA-bridged food emulsion gel as edible ink for 3D printing

Objectives:Interdroplet interactions affect the properties and textures of emulsions.In this study,we creatively introduced telechelic DNA to link oil droplets directly at molecular scale to further improve the viscoelastic properties of emulsions.Materials and Methods:A stable emulsion with 70%oil fraction was prepared by adding 40 mg/mL of whey protein isolate and peach gum polysaccharide complex(WPI–PGP complex).The addition of telechelic DNA(0.125–0.375μmol/L)made the emulsion change from a cream-like state to a self-supporting gel.Results:Rheological experiments confirmed that the telechelic DNA could improve the yield stress,storage modulus/loss modulus(Gʹ/Gʹʹ)and apparent viscosity of the emulsion gel in a concentration-dependent manner(0–0.375μmol/L).Inverted fluorescence images clearly showed the interdroplet network of the emulsion gel linked by telechelic DNA.For 3D printing,the emulsion gel with a higher concentration(0.375μmol/L)of telechelic DNA displayed better surface quality and dimensional resolution,indicating improved printability.Conclusion:This study successfully designed a novel telechelic DNA-bridged emulsion gel,which showed great potential as edible ink for 3D printing.

Covalently Crosslinked Networks from Telechelic Polycyclooctene with Reinforced Properties

Comprehensive Summary Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material properties.In this contribution,well-defined telechelic polymers bearing acetoacetate groups were synthesized via Ru-catalyzed ring-opening metathesis polymerization of cyclooctene in the presence of chain transfer agents.Given the unique feature of muti-site reactive acetoacetate end groups,several crosslinked networks were constructed using different crosslinkers under mild conditions.In the Michael addition reaction system,the introduction of di/trifunctional aliphatic acrylate as crosslinkers significantly enhanced the mechanical properties of the generated crosslinked network(tensile strength up to 27 MPa,elongation at break up to 500%).On the other hand,vitrimers with dynamic covalent crosslinked networks were accessed via transamination of vinylogous urethane reaction using telechelic polymers and tris(2-aminoethyl)amine.

Synthesis of Well-defined Telechelic Trans-1,4-polyisoprene by Oxidative Cleavage

Synthesis of telechelic trans-1,4-polyisoprenes（TPI： trans-structure ＆gt; 95%） was evaluated based on two different methods of oxidative cleavage（indirect cleavage： first epoxidation of TPI, then the selective cleavage of epoxidized units in epoxidized trans-1,4-polyisoprene（ETPI） and direct cleavage of isoprene units in TPI）. The influence of solvents and the ratio of oxidative agents was investigated by 1H-NMR and 13C-NMR. A series of well-defined telechelic TPI with double terminated functional groups and less side reaction（molecular weight distribution range： 1.96？2.26） were synthesized by indirect cleavage in chloroform. Telechelic TPI showed similar crystallization behavior with TPI and interesting cold crystallization behavior characterized by DSC.