ABSTRACT
Polyolefin plastics are a group of polymers with C-C backbone that have been widely used in various areas of daily life. Due to their stable chemical properties and poor biodegradability, polyolefin plastic waste continues to accumulate worldwide, causing serious environmental pollution and ecological crises. In recent years, biological degradation of polyolefin plastics has attracted considerable attention. The abundant microbial resources in the nature offer the possibility of biodegradation of polyolefin plastic waste, and microorganisms capable of degrading polyolefin have been reported. This review summarizes the research progress on the biodegradation microbial resources and the biodegradation mechanisms of polyolefin plastics, presents the current challenges in the biodegradation of polyolefin plastics, and provides an outlook on future research directions.
Subject(s)
Plastics/metabolism , Polymers/metabolism , Polyenes , Biodegradation, EnvironmentalABSTRACT
INTRODUCTION@#Stable distal radius fractures in children are frequently treated by immobilisation with a cast and heal readily without complications. This randomised clinical trial aimed to assess patient satisfaction and casting-related clinical outcomes when using polyolefin cast, a new cast material, compared to the conventional fibreglass cast.@*METHODS@#A total of 80 patients (age range 7-16 years) with radiograph-confirmed stable distal radius fractures were recruited. They were randomised to either the fibreglass group or polyolefin group, with short arm cast immobilisation for 20-30 days. After cast removal, the incidence of skin rash, growth of hair and cast breakage was recorded along with the administration of patient satisfaction questionnaires. Mann-Whitney U test or Fisher's exact test was applied to compare results.@*RESULTS@#Overall, 34 patients from the fibreglass group and 31 patients from the polyolefin group were included in the final analysis. Significantly fewer patients from the polyolefin group reported itchiness during the casting period (p = 0.038). However, significantly more cast breakages were observed for the polyolefin group in the palmar bar region (p = 0.009). Patients from the polyolefin group were overall more satisfied (fibreglass group = 3.15/5 vs. polyolefin group = 3.74/5; p = 0.002).@*CONCLUSION@#Polyolefin cast reduces itchiness during casting and provides higher overall patient satisfaction during the treatment of stable distal radius fractures in children in tropical climates. However, patients should be counselled regarding potential cast breakage, which did not compromise safety, and the higher costs involved.
ABSTRACT
Shape-memory polymers(SMPs) can retain a temporary shape after pre-deformation at an elevated temperature and subsequent cooling to a lower temperature.When reheated,the original shape can be recovered.The development of the research on polyolefin,polyurethanes,polyester and some other shape-memory polymers were introduced and their applications in medical equipment were reviewed.