ABSTRACT
BACKGROUND:Shape memory polymer is a new type of functional material. The applications of shape memory polymers in the biomedical field have increasingly been paid close attention. OBJECTIVE: To summarize the characteristics and applications of shape memory polymers. METHODS: SpringerLink and China Journal Ful text Database were searched for articles related to shape memory polymers. RESULTS AND CONCLUSION: As a new type of inteligence material, shape memory polymers have lots of advantages compared with shape memory aloy and shape memory ceramics, such as low density, light weight, low cost, high shape-recovery rate, easy to regulate the shape memory temperature, to dye, to shape and to be stimulated under expected switch temperature. Especialy for polyurethane, the structure-property relationships are extremely easy to control, the shape memory temperature can be set in a wide range from-30℃ to 70℃, and it has the biocompatibility. Due to these, shape memory polymers have great potentials in applications of biomedical engineering. But the comprehensive properties of the developed shape memory polymers are not satisfactory. For example, the polynorbornene has big recovery stress, fast recovery velocity and high recovery precision, but its relative molecular mass is very big, the molecularchain is long, and processing is difficult. Furthermore, most of shape memory polymers have smal recovery stress, slow recovery velocity, low recovery precision and unsatisfied repeat memory effect. The key problems for shape memory polymers include optimization of the function of shape memory and improvement of the comprehensive properties based on the technologies of molecular design and material modification.