North University of China

Shanxi Zhongbei New Material Technology Co., Ltd.

Northen University of China

Yang Xiang

Yaqing Liu

Guizhe Zhao

Mingshan Gong

Wei Zhang

Wenqi Wang

Taian Chen

This disclosure relates to slow- and controlled-release fertilizers, and more particularly to a device and a method for industrialized continuous and simplified preparing a urea-formaldehyde slow-release nitrogen fertilizer or a urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer. Hydroxymethylurea is produced through the reaction extrusion of urea and formaldehyde. Through the self-ploycondensation of the hydroxymethylurea or the co-polymerization of the hydroxymethylurea and a modifier in a reactive extruder, the urea-formaldehyde slow-release nitrogen fertilizer or the urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer is prepared.

Device and method for industrialized continuous and simplified preparation of urea-formaldehyde slow-release nitrogen fertilizer or urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer

A method for integrally preparing urea-formaldehyde (UF)-based multi-nutrient biodegradable polymeric slow-release (SR) liquid and granular fertilizers is provided. A hydroxymethylurea solution is prepared, and a part of the hydroxymethylurea solution is added to a reactor for reaction to obtain the UF-based multi-nutrient biodegradable polymeric SR liquid fertilizer. The rest of the hydroxymethylurea solution is fed into a reaction-extrusion integrated machine for reactive extrusion to obtain a UF polymer through the polycondensation reaction, which is extruded, dried and granulated to obtain the UF-based multi-nutrient biodegradable polymeric SR granular fertilizer. A method for applying such liquid and granular fertilizers is also provided.

Integrated-preparation and application methods of urea-formaldehyde (UF)-based multi-nutrient biodegradable polymeric slow-release (SR) liquid and granular fertilizers

Disclosed is a method for preparing a nitrogen-rich or nutritious straw-based slow-release fertilizer through In-Situ straw modification/reactive extrusion integrated continuous process. In the method, the liquid reaction precursor of a nitrogen-containing biodegradable slow-release fertilizer is mixed with crop straw to obtain a reaction mixture, or the liquid reaction precursor of a nitrogen-containing biodegradable slow-release fertilizer, crop straw and a soluble fertilizer are mixed to obtain a reaction mixture. The reaction mixture is subjected to extrusion in a screw extruder to produce the nitrogen-rich or nutritious straw-based slow-release fertilizer.

Method for preparing nitrogen-rich or nutritious slow-release fertilizer through in-situ straw modification/reactive extrusion integrated continuous process

A method of producing a thermoplastic starch by an in-situ reactive extrusion plasticization process and a method for preparing a starch/polymer blend by an in-situ reactive extrusion plasticization and compatibilization process. In the method, a plasticizer reaction precursor (or a plasticizing compatibilizer reaction precursor) is mixed with starch to adhere to the surface of the starch or enter the starch to break the intermolecular and intramolecular hydrogen bonds of the starch. Then a mixture of the plasticizer reaction precursor (or the plasticizing compatibilizer reaction precursor) and starch is subjected to extrusion to produce the thermoplastic starch (or the starch/polymer blend), where the reaction precursor undergoes an in-situ reaction on the surfaces of the starch and in the starch to form a macro-molecular plasticizer (or a plasticizing compatibilizer) to plasticize starch or provide plasticizing and compatibilizing effect on the starch/polymer blend.

Method for preparing thermoplastic starch by in-situ reactive extrusion plasticization process and method for preparing starch/polymer blend by in-situ reactive extrusion plasticization and compatibilization process

A device for determining degradation rate of biodegradable polymers in soil, including a micro compressed air pump, a first COabsorption vessel filled with dry soda lime or an aqueous strong alkali solution, a COindicator vessel filled with a barium hydroxide solution, a hollow leaching device, a second COabsorption vessel and a third COabsorption vessel connected in sequence through connecting pipes. A top of the hollow leaching device is provided with an end cover. An external water distributor filled with a leaching solution and a mechanical stirring device is arranged above the end cover. The external water distributor is in communication with an inner cavity of the hollow leaching device through a pipeline. A stirring shaft of the mechanical stirring device extends into the inner cavity. A stirring shaft is provided with a stirring paddle.

Device and method for determining degradation rate of biodegradable polymers in soil

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.

Preparation of urea-formaldehyde/poly(butylene succinate) and its ternary biodegradable polymer nano slow/controlled release materials by reactive extrusion

A method for continuously preparing graphene powder directly dispersed in an organic system, including: mixing an aqueous graphene oxide dispersion, an emulsifier and an oil-soluble monomer followed by pH adjustment and dispersing to obtain a pre-emulsified dispersion; subjecting the pre-emulsified dispersion to an emulsion polymerization reaction in the presence of an initiator; introducing a reducing agent to reduce graphene oxide; and subjecting the reaction mixture after emulsion polymerization to spray drying to obtain the graphene powder. Equipment used in the preparation method is also provided herein.

Equipment and method for continuously preparing graphene powder directly dispersed in organic system

The invention relates to the field of slow/controlled release fertilizer, in particular to a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer and a preparation method thereof. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprises ammonium polyphosphate, inorganic silica gel and urea-formaldehyde, wherein the phosphorus-oxygen double bond of ammonium polyphosphate can at least form hydrogen bond linkage with a urea-formaldehyde molecule chain, the hydroxyl group of the inorganic silica gel can at least form hydrogen bond linkage with the urea-formaldehyde molecular chain, and ammonium polyphosphate, inorganic silica gel and urea-formaldehyde together form a hydrogen bond associated polymer network structure. The invention can prepare a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprising a strong hydrogen bond network structure by using a conventional aqueous solution polymerization in combination with a normal temperature extrusion granulation process, avoiding the coating process in the latter stage of the preparation of a coated fertilizer, achieving a simple and effective preparation process, and saving a lot of manpower and material resources. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer provided by the invention can stably and continuously release nitrogen nutrient throughout the release period, thereby making up for the shortcoming of excessively long nutrient release period of the existing urea-formaldehyde fertilizers.

Extrusion granulated urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer and preparation method thereof

This disclosure relates to water-absorbing and slow/controlled release fertilizer, in particular to a water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure, and preparation methods thereof. The method can comprises the steps of: reacting formaldehyde with urea to obtain a hydroxymethyl urea solution; adding acrylic acid and acrylamide monomers into another reactor, and adding a KOH solution to adjust the neutralization degree of acrylic acid, then adding one of inorganic clay, pretreated crop straw or cellulose, then adding initiator, monopotassium phosphate and the prepared hydroxymethyl urea solution sequentially; allowing to react at temperature after being mixed uniformly to obtain a viscous product; and granulating the viscous product and oven drying the same to obtain the fertilizer. The fertilizer prepared according to the present invention has strong water-absorbing and water-retaining capacity, and an excellent slow release performance for nitrogen, phosphorus and potassium contained as nutrients.

Water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure

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Taiyuan, China

Yang Xiang