Scientists have developed a new generation of rigid, recyclable heat shrinkable tubes.
The heat shrinkable tube has the functions of high temperature shrinkage, soft flame retardant, insulation and anticorrosion. Since Raychem applied for the first patent for polyethylene heat shrinkable tubes in 1959, researchers around the world have been looking for ways to improve the performance of heat shrinkable tubes.
Recently, scientists in China have made breakthroughs in this area. Xiao Xinli and Kong Deyan of Harbin Institute of Technology have successfully prepared a new generation of heat shrinkable tubes which can be recycled to withstand extreme environment with the help of polyimide. Their results were recently published in the Sci.Rep.7449362017.
The heat shrinkable tube is a polymer with shape memory function. It expands at high temperature, and then uses fast cooling technology to fix the state of expansion. When the reheating reaches the full recovery temperature, the heat shrinkable tube shrinks back to its original state. Therefore, the complete restoration of temperature determines its application scope and field.
The thermal shrinkage of the traditional heat shrinkable tube is different from the irreversible crystalline melting. The thermal shrinkage of the polyimide heat shrinkable tube is derived from the reversible glass transition of polyimide. The complete recovery temperature is adjustable between 180 and 330 C, and the tolerable low temperature is also extended from -40 C to -80 C to -196 C. This not only solves the problem that the traditional heat shrinkable tubes can not be recycled, but also greatly expands the working temperature of the heat shrinkable tubes.