| 摘要 |
An amorphous polylactic acid polymer having a weight average molecular weight of about 35,000 to 45,000 is described. The polylactic acid polymer composition can be of particles wherein 90% of the particles have a size of 250 nm or less, a glass transition temperature about 55 to 58 degrees centigrade, and a relative viscosity at 30 degrees centigrade between 1.65 to 1.95. The polymer composition can be used to form an aqueous suspension. The material is ideal in preparing particleboards. A method is disclosed for preparing such polylactic acid polymers. The method involves obtaining an amorphous polylactic acid polymer having a weight average molecular weight of between 115,000 to 180,000. Treating the polylactic acid polymer to reduce the molecular weight between 35,000 to 45,000 such that the glass transition temperature is about 55 to 58 degrees centigrade and a relative viscosity at 30 degrees centigrade about 1.65 to 1.95. 90% of the particles must have an average diameter of 250 nm or less. |
