title: Light-induced catalyst and solvent-free high pressure synthesis of high density polyethylene at ambient temperature.
abstract: The combined effect of high pressure and electronic photo-excitation has been proven to be very efficient in activating extremely selective polymerisations of small unsaturated hydrocarbons in diamond anvil cells (DAC). Here we report an ambient temperature, large volume synthesis of high density polyethylene based only on high pressure (0.4-0.5 GPa) and photo-excitation (~350 nm), without any solvent, catalyst or radical initiator. The reaction conditions are accessible to the current industrial technology and the laboratory scale pilot reactor can be scaled up to much larger dimensions for practical applications. FTIR and Raman spectroscopy, and X-ray diffraction, indicate that the synthesised material is of comparable quality with respect to the outstanding crystalline material obtained in the DAC. The polydispersity index is comparable to that of IV generation Ziegler-Natta catalysts. Moreover the crystalline quality of the synthesised material can be further enhanced by a thermal annealing at 373 K and ambient pressure.
authors.affiliation: ICCOM-CNR, Institute of Chemistry of OrganoMetallic Compounds, National Research Council of Italy, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Firenze, Italy; LENS, European Laboratory for Non-Linear Spectroscopy, Via N. Carrara 1, I-50019, Sesto Fiorentino, Firenze, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Ceppatelli
authors.forename: Roberto
authors.initials: R
authors.lastname: Bini
mesh_terms: D002384:Catalysis / Q000528:radiation effects; D003460:Crystallization; D008027:Light; D020959:Polyethylene / Q000138:chemical synthesis* / Q000737:chemistry; D011312:Pressure; D012997:Solvents; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D012997:Solvents; D020959:Polyethylene
keywords: ethylene polymerisation; green chemistry; high pressure chemistry; photochemistry; polyethylene