Brzina dugotrajnoga higroskopskog debljinskog bubrenja kompozita od polipropilena i hidrotermički tretirane bukovine

Long-term hygroscopic thickness swelling rate of polypropylene (PP) composites filled with thermally treated wood flour was investigated. The beech wood chips were heat treated at 120 °C, 150 °C or 180 °C for 30 or 120 min using saturated steam in a digester. The composites based on PP, beech wood flour (BF), and coupling agents (PP-g-MA) were made by melt compounding and injection molding. The weight ratio of BF to PP was controlled at 50/47 for all blends. The amount of coupling agent was fixed at 3 wt.% for all formulations. Further study was conducted to model thickness swelling of the composites, a swelling rate parameter (KSR). The thickness swelling of thermally-treated samples at 120 ºC for 30 min and at 150 ºC for 30 min were lower than that of control samples, followed by thermally-treated samples at 180 ºC for 120 min, at 180 ºC for 30 min, at 120 ºC for 120 min, and at 150 ºC for 120 min, respectively. Furthermore, the thickness swelling of the BF/PP composites decreased with increasing time and temperature of the thermal-treatment. In addition, at 120 ºC for 30 min, the composites showed a lower swelling rate than control samples. The KSR of the composites was influenced both by the time and temperature of thermal treatment.U radu je istražen dugotrajni stupanj higroskopskoga debljinskog bubrenja polipropilenskih (PP) kompozita punjenih toplinski obrađenim drvnim brašnom. Iverje od bukovine bilo je toplinski tretirano na 120, 150 ili 180 °C tijekom 30 ili 120 minuta uz pomoć zasićene pare u digestoru. Kompoziti na bazi PP-a, brašna od bukovine (BF)-a i veziva (PP-g-MA) izrađeni su taljenjem i injekcijskim prešanjem. Maseni je omjer BF/PP za sve smjese bio 50/47. Količina veziva za sve formulacije bila je na 3 wt.%. Nadalje, provedeno je modeliranje debljinskog bubrenja kompozita i parametra brzine bubrenja (KSR). Debljinsko bubrenje uzoraka toplinski tretiranih 30 min na 120 ºC i 30 min na 150 ºC bilo je niže nego na kontrolnim uzorcima, zatim slijede uzorci toplinski tretirani 120 min na 180 ºC, 30 min na 180 ºC, 120 min na 120 ºC, odnosno 120 min na 150 ºC. Nadalje, debljinsko bubrenje BF/PP kompozita smanjivalo se s povećanjem vremena i temperature toplinskog postupka. Osim toga, kompoziti su pri 30 min na 120 ºC pokazali niži parametar brzine bubrenja od kontrolnih uzoraka. Na parametar brzine bubrenja kompozita utjecali su vrijeme toplinskog tretmana i temperatura

Surgical Decompression of Thoracic Ossification of the Posterior Longitudinal Ligament through Posterior Approach: A Case Report

Thoracic ossification of the posterior longitudinal ligament (OPLL) is a rare condition that is mainlyaccompanied by cervical OPLL or ossification of thoracic ligamentum flavum. In case of causing neurologicalmanifestations, it is preferred to treat the condition surgically. Several surgical procedures were introduced,including anterior, posterior, or combined approaches. Laminectomy with instrumented fusion is the mostpopular procedure utilized via the posterior approach. A 32-year-old obese woman, who suffered from backpain and weakness in both lower extremities for one month, was referred to our spine outpatient clinic. Imagingrevealed lower thoracic OPLL (T7/T8 & T8/T9 & T9/T10). The posterior longitudinal ligament had a mixedossification pattern (beaked and continuing cylindrical). To maintain thoracic spine stability and prevent futurekyphosis, we performed laminectomy and long segment fixation (T7 to T12). The post-operative neurologicalexamination revealed a considerable increase in muscle strength and significant pain relief

Investigation on the properties of oriented strand boards (OSB) made from mixture ten- year- old poplar clones

In this study, the effects of mat moisture content and press temperature on physical and mechanical properties of three layered oriented strand boards were evaluated. Two levels of mat moisture content 7% and 10% and three levels of press temperature 180 ˚c , 200 ˚c and 220 ˚c were applied and 12 mm in nominal thickness laboratory boards were made from mixture of three clones of ten-year-old hybrid poplar ( populous euramericana vernirubensis, p. e. I-214, P. e. 561/41) while the strands on the surface layers are aligned in the long direction of the board and the middle layer strands are cross aligned to the surface layers. In all treatments, board targeted density of 0/7 g/cm3 and press time of 8 min and phenol-formaldehyde resin (PF) content of 7% based on the oven dry weight of the strands were held constant. The mechanical and physical properties of the boards were measured as defined in relevant European standards EN 300 for OSB/1 and OSB/2. Overall results showed that all boards made from above mentioned conditions exceed the EN 300 standards for MOR, MOE, IB and TS24. The bending properties (MOR and MOE) of boards were significantly improved as the mat moisture content increased from 7 to 10%. The highest MOR was achieved at 10% mat moisture content and 220 ˚c press temperature and the highest MOE was achieved at 10% mat moisture content and 180 ˚c press temperature. The Modulus of Rupture (MOR) and Thickness swelling (TS24) were significantly improved as the press temperature increased from 180 ˚c to 220 ˚c. The lowest TS24 was achieved at 7% mat moisture content and 220 ˚c press temperature and the highest IB was achieved at 7% mat moisture content and 200 ˚c press temperature

Use of black locust/poplar wood as filler in thermoplastic composites

Wood plastic composites (WPCs) were produced from different mixtures (up to 45% by weight) of poplar (Populus alba L.) and pruning branches of black locust (Robinia pseudoacacia) wood flours, polypropylene (53 wt.%), and maleic anhydride-grafted polypropylene (2 wt.%). Weight loss, flexural strength (MOR), flexural modulus (MOE), notched impact strength (IS), water absorption (WA), and thickness swelling (TS) of WPCs after 24 h of immersion in distilled water were determined before and after incubation with white-rot fungus (Trametes versicolor) for 7 weeks. The MOR and MOE increased with an increase in poplar wood in the WPC. The notched IS decreased with an increase in black locust wood and poplar wood in the WPC. The weight loss in WPCs exposed to white-rot fungus was minimal for WPCs with a high amount of black locust pruning branch flour. The MOR and MOE declined after incubation with fungus. Fungal decay had a significant influence on the notched IS. Furthermore, the results indicated that the WA and TS of white-rotted WPCs for all the WPC formulations were significantly higher than those of unrotted WPCs

Use of black locust/poplar wood as filler in thermoplastic composites

Wood plastic composites (WPCs) were produced from different mixtures (up to 45% by weight) of poplar (Populus alba L.) and pruning branches of black locust (Robinia pseudoacacia) wood flours, polypropylene (53 wt.%), and maleic anhydride-grafted polypropylene (2 wt.%). Weight loss, flexural strength (MOR), flexural modulus (MOE), notched impact strength (IS), water absorption (WA), and thickness swelling (TS) of WPCs after 24 h of immersion in distilled water were determined before and after incubation with white-rot fungus (Trametes versicolor) for 7 weeks. The MOR and MOE increased with an increase in poplar wood in the WPC. The notched IS decreased with an increase in black locust wood and poplar wood in the WPC. The weight loss in WPCs exposed to white-rot fungus was minimal for WPCs with a high amount of black locust pruning branch flour. The MOR and MOE declined after incubation with fungus. Fungal decay had a significant influence on the notched IS. Furthermore, the results indicated that the WA and TS of white-rotted WPCs for all the WPC formulations were significantly higher than those of unrotted WPCs