Effects of Accelerated Weathering in Polylactide Biocomposites Reinforced with Microcrystalline Cellulose

The aim of this study was to reveal effects of accelerated weathering in neat polylactide (PLA) and its biocomposite reinforced with microcrystalline cellulose (MCC); compounded by twin-screw extrusion melt mixing and specimen shaping by injection molding. Weathering conditions were applied via consecutive steps of UV irradiation and humidity in accordance with ISO 4892–3 standards for 200 h. Various characterization techniques and mechanical tests indicated that photolysis, photo-oxidation and hydrolysis were the main degradation mechanisms leading to significant decrease in the molecular weight of PLA via main chain scission. Consequently, except elastic modulus other mechanical properties; strength, ductility and fracture toughness of PLA and PLA/MCC decreased substantially. However, after comparing the mechanical properties of the neat PLA and PLA/MCC biocomposite specimens having 200 h of accelerated weathering, it was concluded that; for the outdoor applications use of PLA/MCC biocomposite (with only 3 wt% MCC) was extremely beneficial compared to using neat PLA. For example, tensile strength is more than 91 % beneficial while strain at break ductility is more than 2.7 times beneficial.

Reliability and validity of the Turkish version of the ECOS 16 questionnaire in postmenopausal osteoporosis

AIM

The purpose of this study was to develop a Turkish version of ECOS 16 Questionnaire and assess its reliability and validity.

METHODS

Sixty four women with postmenopausal osteoporosis were included in the study. It was mandatory for all patients to be Turkish literate and without symptoms of dementia. Patients who were diagnosed as secondary osteoporosis by clinical and laboratory examinations were excluded from the study. After translation process, the Turkish version of the scale was applied to each participant twice with an interval of 2 weeks. For reliability study, internal consistency (Chronbach alpha) of ECOS 16 total score and test-retest intraclass correlation coefficient (ICC) were calculated. Validation study was assessed by correlating the scale with QUALEFFO 41.

RESULTS

The mean age at menopause and age of patients were 45.61+/-6.04 years and 59.91+/-8.69 years respectively. Chronbach alpha of the Turkish version of the ECOS 16 was 0.90. The test-retest reliability (ICC) of the Turkish version of the ECOS 16 was determined as 0.83 for the total score, and ranged between 0.72-0.88 for individual items. In terms of validity; the Turkish version of ECOS 16 correlated significantly with QUALEFFO 41 (r=0.844 P<0.0001).

CONCLUSIONS

. The Turkish version of the ECOS 16 is a reliable and valid questionnaire to be used in the evaluation of Turkish women with postmenopausal osteoporosis.