Ventilation and ventilation can increase the oxygen content of the mushroom shed, but the cold air outside the shed will invade the shed, thereby reducing the temperature of the shed. Therefore, in the winter, under the premise of ensuring adequate oxygen in the shed, ventilation time should be reduced as much as possible. For larger sheds with good ventilation, the shed should be ventilated for a short period of time with a small amount of ventilation. It can be ventilated for 3 to 4 times a day for 30 minutes each time; on the contrary, it should be ventilated for 8 to 10 times, each for 20 minutes. At the same time, man-made movements are used to allow proper ventilation of dead corners.
PHB is a truly biodegradable and biocompatible plastic and an attractive environmental-friendly alternative to fossil-based thermoplastics such as PE and PP. However, unmodified PHB resin has a relatively high melting point of about 160 to 180 °C and is difficult to process due to its narrow processing window. To improve its processability and mechanical properties, PHB is often blended with plasticizers and other polymers such as polyvinyl acetate (binders), polyvinyl alcohol and polylactic acid (PLA).
Commercial grades of PHB have properties that are very similar to those of polypropylene (PP). Typical applications of PHB are disposable tableware articles like drinking cups, cutlery, trays, food plates and food containers. Some other (potential) applications include soil retention sheething and other agriculture films, waste and shopping bags, and the use as a packaging material in general. PHB can also be spun into fibers which could be used for the manufacture of woven and non-woven biodegradable one-use fabric articles such as surgical sutures (Tepha). Other (potential) biomedical applications include drug delivery systems (microcapsules or microspheres) and biodegradable implanted medical devices.
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