Structure, thermal and mechanical properties of poly (ε-caprolactone)/organomodified clay bionanocomposites prepared in open air by in situ polymerization

The first example of the usefulness of titanium (IV) butoxide, as initiators for open air in-situ intercalative polymerization of ε-caprolactone (ε-CL) in the presence of organoclay is herein reported. The bionanocomposites based on poly(ε-caprolactone) (PCL) were prepared by in-situ Ring Opening Polymerization (ROP) of ε-caprolactone in the presence of different organomodified montmorillonite clay (ODA-MMT) loading (1, 3 and wt%). Structural, thermal and mechanical characterizations of the resulting bionanocomposites were investigated. The presence of the nanoclay increased PCL crystallinity, melting temperature and thermal stability, whereas some decrease in T was observed. TEM analyses confirmed the good dispersion of ODA-MMT with 1 and 3 wt% content into the PCL polymer as already asserted by XRD diffraction. Finally, the Young's modulus of the PCL nanocomposites was higher compared to the neat PCL, while a decrease of stress and strain at break for materials with different filler content was observed.Financial support for cooperative research came from the Hassan II Academy of Science and Technology of Morocco/CSIC-Spain (Project AH11STC-nano 2011 – 2012 and 2010MA003), the MESRSFC and CNRST of Morocco (PPR program), and the bilateral scientific committee programs of collaboration between Morocco and Tunisia (n 17/TM/20), and the Spanish Ministry of Science and Innovation (MICINN) through the project MAT2016-81138-R

Deterioration of long-term results following high tibial osteotomy in patients under 60 years of age

We have investigated, in a prospective study, the outcome of a valgus osteotomy of the tibia in patients less than 60 years of age with arthrosis of the medial compartment and a varus angle of no more than 177.7°. Included in the study were 44 high tibial osteotomies (HTO) performed in 42 patients from 1981 until 1996. There were 35 females (2 bilateral) and 7 males, with an average age of 51 years (range: 30–60 years). Only patients in the first three grades, according to Ahlback’s classification, were included. During a mean follow-up period of 10 years (range: 5–17 years), all but 2 patients experienced pain relief. The average loss of postoperative correction at 10 years was 2.4°. The average postoperative Hospital for Special Surgery Knee Rating System score (HSSK) for patients with excellent or good results was 83.5 points. Survivorship analysis showed a success rate of 80% and 66% at 10 and 15 years respectively, and over 52.8% at 17 years of follow-up. HTO results in redistribution of the main stresses towards normal levels, although normal values are never attained. This is probably the reason why patients experienced good results only in the medium term