Patent ID: 11732078

Abstract:
The invention relates to the field of preparing biodegradable polymer slow/controlled release composite, in particular to a biodegradable polymer slow/controlled release binary composite urea-formaldehyde/poly(butylene succinate) and a biodegradable polymer slow/controlled release ternary nanocomposite urea-formaldehyde/poly(butylene succinate)/potassium dihydrogen phosphate. The following steps are included: uniformly mixing two components poly(butylene succinate) and methylol-urea or three components poly(butylene succinate), methylol-urea and potassium dihydrogen phosphate, and then extruding the resulting mixture by an extruder, and the biodegradable polymer slow/controlled release composite urea-formaldehyde/poly(butylene succinate) containing nutrient N and the biodegradable polymer slow/controlled release nanocomposite urea-formaldehyde/poly(butylene succinate)/potassium dihydrogen phosphate containing nutrients of N, P and K are obtained respectively. As one of the raw materials, methylol-urea, the precursor of urea-formaldehyde, can react by way of melt polycondensation to form urea-formaldehyde macromolecular chains with different polymerization degrees at high temperature in the extruder, which are dispersed among the PBS macromolecular chains, thereby obtaining the composite UF/PBS of the present invention; and the hindering effect of the molecular segments of urea-formaldehyde and poly(butylene succinate) and the hydrogen bond interaction between the components result in that potassium dihydrogen phosphate crystals dissolved in the water produced by the polycondensation reaction are restricted to nanoscale during their precipitation process, so as to prepare nanocomposite UF/PBS/MKP. The prepared composites all have excellent mechanical properties, and can be directly used as a biodegradable polymer slow/controlled release fertilizer, or as a matrix polymer to prepare other types of slow release fertilizers, and the formulae with high PBS contents can also replace PBS to prepare other agricultural implements, such as agricultural films, nursery pots and vegetation nets.