Structural and Thermal Properties of Polycaprolactone/PEG-Coated Zinc Oxide Nanocomposites

Abstract: In this paper, PCL with PEG-coated ZnO nanocomposites films were prepared by solution casting using dichloromethane as a solvent. ZnO nanoparticles of 24 nm crystallite size were synthesized by chemical precipitation method. Surface modification of ZnO NPs was achieved by solution mixing with low molecular weight PEG and verified by FTIR and TGA. The nanocomposites films were characterized by XRD, FTIR, SEM, and TGA techniques. PEG surface modification of ZnO leads to well-dispersed nanoparticles in the polymer matrix. The incorporation of ZnO NPs in PCL alters the thermal stability of the polymer by up to 110°C degradation onset temperature. Non-isothermal kinetic study was performed by model-fitting Coats-Redfern method. The calculated activation energies of the nanocomposites indicate the catalytic effect of ZnO on the thermal decomposition of PCL.The authors would like to acknowledge the assistance of the ICTP-CSIC technical staff

Structural characterization and thermal degradation of poly(methylmethacrylate)/zinc oxide nanocomposites

This work is based on the preparation of composites of poly(methylmethacrylate) with zinc oxide nanoparticles synthesized by solution casting method. Chloroform cast poly(methylmethacrylate) films containing different amounts of ZnO nanoparticles were characterized by XRD, SEM, UV-vis spectroscopy, FTIR spectroscopy and TGA. The results show that ZnO nanoparticles with a size of 24 nm were fairly dispersed in the polymer matrix. The obtained material had UV shielding capability with optical transparency. Thermal characterization shows that, the nanocomposites were more thermally stable than pure PMMA presenting three degradation steps. Apparent kinetic parameters were determined for each degradation step using peak fitting methodology. According to activation energies, ZnO particles affect simultaneously but oppositely the kinetics of underlying degradation reactions. Thermal stability of the PMMA/ZnO nanocomposites was the result of the overall balance in favor of the inhibiting effect of ZnO.The authors acknowledge the financial support of CNEPRU project N E00720140050. MALM thanks the support from the MINECO project MAT2016-81138-R. The authors appreciate the assistance of ICTP/ SCIC technical staff.Peer Reviewe

Reduction of hydrogen embrittlement of API 5l X65 steel pipe using a green inhibitor

International audienc

Corrosion Inspection and Recommendation on the Internal Wall Degradation Caused Rupture of 6” Gas Line Pipe

International audienceA sudden leak of 6-inch gas line pipe after being in service for 1 year was observed. The pipe was designed to transport dry gas. The failure had taken place in 6 o’clock position at the stage discharge of the flow process. Specimens from the failed part had taken for laboratory investigation in order to find out the cause of the pipe rupture. Visual and metallographic observations confirmed that the pipe split was due to a crack initiated in circumferential and then turned into longitudinal direction. Sever wall thickness reduction was noticed on the internal pipe surface. SEM observations at the fracture surface revealed features of ductile fracture mode. Corrosion product analysis showed the traces of iron carbonate/iron sulphate. Upon the laboratory analysis, the concluded remarks confirmed that the pipe failed due to the effect of wet fluid (condensate) caused severe wall thickness dissolution resulted in pipe could not stand the continuation at in-service working condition