33results about How to "Reduce water absorption rate" patented technology

The invention discloses low-hygroscopicity epoxy resin and a preparation method thereof and relates to epoxy resin. The low-hygroscopicity epoxy resin consists of epoxy resin, a curing agent and organic titanium hybrid silsesquioxane, wherein the dosage of the organic titanium hybrid silsesquioxane is 1-20% of that of the epoxy resin by mass; and the dosage of the curing agent is in a stoichiometric ratio to the epoxide equivalent of the epoxy resin. The preparation method comprises the following steps: putting the epoxy resin into a container and heating and stirring; adding organic titanium hybrid silsesquioxane for reacting while performing vacuum suction of small molecules; adding the curing agent; stirring uniformly and pouring into a preheated mould; curing for 4h at 120-130 DEG C; preserving heat for 2h at 130-150 DEG C; and finally, preserving heat for 2h at 150-170 DEG C, and molding to obtain the low-hygroscopicity epoxy resin. The water absorption of the epoxy resin is reduced, and the crosslinking density of the resin is increased; and meanwhile, the mechanical property and heat resistance of the epoxy resin are improved, and the barrier performance of the epoxy resin is enhanced.

The invention discloses a polyester fiber-reinforced injection-type phenolic aldehyde molding compound and a preparation method thereof. The polyester fiber-reinforced injection-type phenolic aldehyde molding compound is mainly prepared from a linear phenolic resin, hexamethylene tetramine, an inorganic filling material and polyester fibers. The preparation method comprises the following steps of 1, weighing raw materials for next use, 2, putting the inorganic filling material and a coupling agent into a ball mill or a ball milling tank, and carrying out ball milling to obtain a uniform mixture, wherein the use amount of the coupling agent is 0.5-10wt% of that of the inorganic filling material and the inorganic filling material comprises one or more of aluminum hydroxide, silica micropowder, calcite, talc, calcium carbonate, glass beads, kaolin and clay powder, 3, crushing hexamethylene tetramine, mixing the crushed hexamethylene tetramine and the inorganic filling material and other raw materials subjected to surface treatment to obtain a uniform mixture, 4, putting the mixture into a double screw extruder and carrying out extrusion and 5, cooling the extruded material and carrying out crushing. The polyester fiber-reinforced injection-type phenolic aldehyde molding compound obtained by the preparation method has high mechanical properties and low water absorbency.

The invention provides a preparation method of a silane modified concrete internal curing agent. The preparation method comprises steps as follows: inorganic clay is completely dispersed in deionized water, a neutralized acrylic acid solution, a cross-linking agent and an initiator are added and uniformly mixed, the mixture is heated to 40-60 DEG C and reacts for 8-12 h, superabsorbent resin gel is obtained and subjected to granulation, drying, crushing, screening and surface crosslinking, and superabsorbent resin is obtained; a silane coupling agent is dissolved in ethanol, the superabsorbent resin is added to be sufficiently mixed, the mixture is put in an oven at the temperature of 100-140 DEG C and reacts for 1-2 h, and the final concrete internal curing agent is obtained. According to the method, a preparation process is simple and convenient, a chemical structure is easy to control, the prepared internal curing agent has a lower water absorption rate, influence of the internal curing agent on workability of concrete can be reduced, the early self-constriction and reduction effect of the concrete is improved, and the problem of early cracking of the concrete is solved.

The invention relates to a slab joint shoving material for an ALC external wallboard and a preparation method thereof. The slab joint shoving material is prepared from, by weight, 30-97% of a cementing agent, 1-10 parts of a self-repairing master batch, 1-5 parts of a volume stabilizer, 0-1 part of a defoaming agent, 0-60 parts of filler, 1-10 parts of emulsified paraffin, 0.1-2 parts of a water retaining agent, 0.1-1 part of a thixotropic agent and 0-1 part of a condensing time regulating agent. The slab joint shoving material has the good bonding strength, tensile breaking strength and breaking elongation at break and has the low volume change rate, water absorbing rate and water absorbing speed; meanwhile, the slab joint shoving material further has the certain micro-crack self-repairing, sealing performance and flexibility, and ensures the engineering quality of an autoclaved aerated concrete external wallboard.

The invention discloses nylon fiber reinforced injectable phenolic moulding plastic and a preparation method of the nylon fiber reinforced injectable phenolic moulding plastic. Raw materials for preparing the phenolic moulding plastic mainly include novolac resin, hexamethylenetetramine, an inorganic filler and nylon fiber. The preparation method of the phenolic moulding plastic comprises the following steps: (1) weighing all the raw materials for later use; (2) placing the inorganic filler and a coupling agent into a ball mill or a jar mill for uniformly ball milling, wherein the dosage of the coupling agent is 0.5-10wt% of that of the inorganic filler, and the inorganic filler is one or a combination of two or more of aluminum hydroxide, silica powder, calcite, talc, calcium carbonate, glass beads, kaolin and pottery clay powder; (3) grinding hexamethylenetetramine, and then evenly mixing with the inorganic filler after surface treatment and other raw materials; (4) putting the mixed materials into a twin-screw extruder for extrusion; (5) grinding extrudate after cooling to obtain the nylon fiber reinforced injectable phenolic moulding plastic. The phenolic moulding plastic prepared by the method is higher in mechanical properties and lower in water absorption.

The invention provides a preparation method of a silane modified concrete internal curing agent. The preparation method comprises steps as follows: polyvinyl alcohol is completely dissolved in deionized water, a neutralized acrylic acid solution, a cross-linking agent and an initiator are added and uniformly mixed, the mixture is heated to 40-60 DEG C and reacts for 8-12 h, superabsorbent resin gel is obtained and subjected to granulation, drying, crushing, screening and surface crosslinking, and superabsorbent resin is obtained; a silane coupling agent is dissolved in benzene, the superabsorbent resin is added to be sufficiently mixed, the mixture is put in an oven at the temperature of 120-160 DEG C and reacts for 1-2 h, and the final concrete internal curing agent is obtained. According to the method, a preparation process is simple and convenient, a chemical structure is easy to control, the prepared internal curing agent has a lower water absorption rate, influence of the internal curing agent on workability of concrete can be reduced, the early self-constriction and reduction effect of the concrete is improved, and the problem of early cracking of the concrete is solved.

The invention utilizes the protection mechanism of wheat "seeking advantages and avoiding disadvantages" to provide a screening method for ear-resistant germination wheat varieties (strains), which belongs to the technical field of wheat breeding and comprises the following steps: in the variety (strain) identification nursery, respectively 35, 38 and 40 days after wheat flowering, the wheat ears of each variety (line) were randomly selected; the water loading rate of wheat ears, grain bubbling water demand rate, and grain imbibition stage required for each variety (line) were measured in sequence. Time, dehydration time of soaked wheat ears, grain water absorption rate and grain dehydration rate; calculate the comprehensive ear germination value of each variety in different days and arrange them in size; select the minimum ear germination value of each variety (line) to evaluate, so as to evaluate the wheat The ear germination resistance of varieties (lines) was identified and evaluated. In the present invention, the indicators for mitigating the harm of ear germination are incorporated into the evaluation criteria of ear germination tolerance of wheat varieties (strains), and then the selected wheat varieties (strains) of ear germination tolerance are close to agricultural production.

The invention relates to a biologic polyamide quadripolymer and a synthesis method thereof, and belongs to the field of high molecular materials. The biologic polyamide quadripolymer is characterized in that the structural formula is shown as the specifications, wherein the four chain segments or chain links are arranged randomly. The invention also provides the synthesis method. The biologic polyamide quadripolymer has excellent environmental stability, a thermal crosslinking property, an irradiation crosslinking property and solvent corrosion resistance, and has physical and mechanical properties and a processing property which are equal to those of conventional polyamide.

The invention discloses a nylon 6 composite material with high rigidity and low water absorption. 30-50 parts of alkali glass fiber, 1-2 parts of silane coupling agent solution, 3-5 parts of nano-layered silicate, 5-10 parts of acrylonitrile-butadiene-styrene-terpolymer, polytetrafluoroethylene 1-10 parts of vinyl fluoride, 3-5 parts of toughening agent, 1-5 parts of compatibilizer, 0.1-1 part of heat-resistant agent, 0.1-1 part of antioxidant, 0.1-1 part of lubricant. The present invention still maintains good rigidity under water environment.