CN117624782A

CN117624782A - Open-cell polymer foam and preparation method thereof

Info

Publication number: CN117624782A
Application number: CN202311636803.1A
Authority: CN
Inventors: 包锦标; 郑晓平; 李妍凝; 曹鑫; 周发俊; 周武舜
Original assignee: Ningbo Micro Foam Material Co ltd; Ningbo Yuewei New Materials Technology Co ltd
Current assignee: Ningbo Micro Foam Material Co ltd; Ningbo Yuewei New Materials Technology Co ltd
Priority date: 2023-12-01
Filing date: 2023-12-01
Publication date: 2024-03-01
Anticipated expiration: 2043-12-01
Also published as: CN117624782B

Abstract

The application relates to the technical field of oil absorbing agents, and particularly discloses an open-cell polymer foam and a preparation method thereof. The raw materials used for the open-cell polymer foam comprise high melt strength polypropylene and polyolefin elastomer with the weight ratio of (6-9) to (1-4); the preparation method comprises the following steps: all the raw materials are melted and blended, extruded and injection molded to obtain a polymer sheet, then the polymer sheet is placed in a closed environment, supercritical fluid is introduced into the closed environment at 160-180 ℃ until the system pressure is 10.0-20.0MPa, then the system is cooled to 120-137 ℃, the temperature is kept for reaction for 25-35min, and then the product is obtained after air exhaust and pressure relief. The product of the application can be used for recycling waste oil spilled oil, and has the advantages of strong oil absorption capacity and good rebound resilience performance; in addition, the preparation method effectively improves the number of foam open cells and the mechanical stability of the product.

Description

Open-cell polymer foam and preparation method thereof

Technical Field

The present application relates to the technical field of oil absorbing agents, and more particularly, to an open cell polymer foam and a method for preparing the same.

Background

In recent years, the continuous occurrence of offshore oil leakage and the discharge of industrial waste oil cause serious pollution to the ecological environment, and the solution of the problem of oil spill has become urgent for environmental protection and sustainable development. At present, various cleaning methods have been explored, typical cleaning methods including in situ incineration, oil containment boom, bioremediation, dispersants and oil absorbers. Open cell polymer foam has proven to be the best solution to this problem as an oil absorbent in a variety of cleaning methods. As research continues, many different types of open cell polymer foams have been developed, with the use of polypropylene (PP) foam being most common.

In order to further improve the compression rebound resilience and oil absorption performance of the PP foam, researchers mostly blend and match the PP foam with different substances, for example Mi et al utilize twin-screw extrusion and supercritical carbon dioxide foaming, blend nano polytetrafluoroethylene particles with PP to prepare PP/PTFE composite foam which has better oil absorption performance; zhao et al developed superhydrophobic PP/CNT/sorbitol derivative nanocomposite open cell foams with excellent oil absorption efficiency and reusability through polymer blending and subsequent foaming processes.

However, the cost of polytetrafluoroethylene particles and carbon nanotubes in the above-described technical solutions is too high, making them unsuitable for wide-ranging use in industrial production. In addition, the PP adopts the traditional linear polypropylene, the linear polypropylene has the problems of limited foaming interval, larger influence of the melt strength by temperature and the like, and the expansion ratio of the open-cell polymer foam is influenced, so that the oil absorption performance of the open-cell polymer foam is still further improved. In addition, linear polypropylene tends to produce cells with larger pore sizes (greater than 250 um), which is detrimental to achieving effective oil-water selectivity.

Disclosure of Invention

In order to solve the technical problems, the application provides an open-cell polymer foam and a preparation method of the open-cell polymer foam.

In a first aspect, the present application provides an open cell polymeric foam, which adopts the following technical scheme:

an open cell polymer foam is prepared from high melt strength polypropylene and polyolefin elastomer in a weight ratio of (6-9): (1-4).

By adopting the technical scheme, the high-melt-strength polypropylene is used as the raw material of the open-cell polymer foam, and compared with the traditional linear polypropylene, the high-melt-strength polypropylene has larger foaming space and higher melt strength, has lower sensitivity to temperature fluctuation, is not easy to form large-aperture foam during foaming, and can effectively improve the foaming multiplying power of the foam and reduce the aperture; meanwhile, the polyolefin elastomer is added into the raw material, and the characteristics of small density, good flexibility and larger melt strength difference with high melt strength polypropylene during foaming are utilized, so that the appearance of the foam holes in the copolymer is more random, the open pore content of the polymer foam is increased, the diameter of the foam holes is reduced, the compression rebound resilience is enhanced, and the polymer foam has stronger oil absorption capacity and cyclic oil absorption capacity. The polyolefin elastomer of the present application is a random copolymer of ethylene and any α -olefin (usually 1-butene and 1-octene), and the random copolymer has better compatibility with high melt strength polypropylene and better bonding degree than other elastomers.

Preferably, the weight ratio of the high melt strength polypropylene to the polyolefin elastomer is (6-7): 3-4.

Preferably, the weight ratio of the high melt strength polypropylene to the polyolefin elastomer is 7:3.

According to the technical scheme, as the content of the polyolefin elastomer in the system is increased, the open-cell content of the open-cell polymer foam is gradually increased, the oil absorption capacity and the rebound resilience are also gradually increased, but the mechanical stability of the prepared foam structure is poor due to the fact that the proportion of the polyolefin elastomer is too high, the problem of easy breakage occurs in recycling, the cyclic oil absorption cannot be performed, and the recycling property is poor, so that the application further limits the weight ratio of the high-melt-strength polypropylene to the polyolefin elastomer to be (6-7): 3-4, the finally prepared open-cell polymer foam product has good oil absorption performance and rebound resilience, good mechanical stability and repeated oil absorption capacity, and according to further experimental data, the open-cell polymer foam has the optimal cell diameter and the open-cell structure with optimal mechanical stability when the weight ratio of the high-melt-strength polypropylene to the polyolefin elastomer is 7:3.

Preferably, the polyolefin elastomer is an ethylene-octene copolymer.

Preferably, the ethylene-octene copolymer has an octene molar insertion of 10.48 to 18.55% and a melt index of 1.0g/min.

Preferably, the ethylene-octene copolymer has an octene molar insertion of 18.55%.

By adopting the technical scheme, the ethylene-octene copolymer is used as the polyolefin elastomer, compared with other alpha-olefins, the 1-octene has moderate chain length, the crystallinity of the ethylene-octene copolymer is proper, the compatibility of the ethylene-octene copolymer and high-melt-strength polypropylene is better, the mechanical stability of the foam structure is further enhanced, and the expansion ratio of the open-cell polymer foam is improved.

And, the present application further optimizes the molar insertion of octene into the ethylene-octene copolymer such that the ethylene-octene copolymer has a higher open cell content, smaller cell structure and narrower cell distribution. Wherein, with the increase of octene content, the proportion of ethylene homopolymerization section in the ethylene-octene copolymer is reduced, the crystallinity of the copolymer is reduced, the overall regularity is reduced, the content of amorphous phase is increased, which is beneficial to improving the solubility of supercritical fluid in the ethylene-octene copolymer during foaming, and simultaneously, the lower crystallinity reduces the obstruction of the supercritical fluid leaving the ethylene-octene copolymer matrix during foaming, thereby enhancing the foaming effect of the ethylene-octene copolymer. However, when the octene content is too high, it may exhibit serious shrinkage problems due to its weaker crystal structure, lower compression modulus and higher supercritical fluid permeability, thereby affecting the mechanical stability of the cell structure. According to experimental data, the ethylene-octene copolymer has the optimal foaming effect when the molar insertion rate of octene is 18.55%.

Preferably, the feedstock further comprises a propylene-ethylene elastomer in an amount of 5 to 8wt% of the amount of the high melt strength polypropylene.

By adopting the technical scheme, because the propylene-ethylene elasticity and the high melt strength polypropylene and the polyolefin elastomer have higher compatibility, the compatibility among all components in the melt blend can be further improved, the open cell content of the polymer foam is further improved, the cell diameter is reduced, and the oil absorption performance and the rebound performance of the open cell polymer foam are further improved.

In a second aspect, the present application provides a method of preparing an open cell polymeric foam comprising the steps of:

s1, preparing a polymer sheet: all the raw materials are melted and blended, extruded and injection molded to obtain a polymer sheet;

s2, preparing an open-cell polymer foam: placing the polymer sheet in a closed environment, introducing supercritical fluid into the closed environment at 160-180 ℃ until the system pressure is 10.0-20.0MPa, cooling to 120-137 ℃, carrying out heat preservation reaction for 25-35min, and releasing the supercritical fluid at a pressure relief rate of 100-500MPa/s to obtain the open-cell polymer foam.

Preferably, in the step S2, the system pressure is 13.0MPa, and the cooling temperature is 132 ℃.

The polypropylene with high melt strength and the polyolefin elastomer have crystallinity, so that the foaming process of the polypropylene with high melt strength and the polyolefin elastomer can only be carried out near respective crystallization melting points, certain phase separation phenomenon can occur when foaming is carried out at the same temperature, in order to balance the open cell content and the mechanical stability of a cell structure, the foaming temperature range is limited to be very narrow (150-156 ℃), the foaming effect of the open cell polymer foam is poor due to slight change of the temperature in the preparation process, and the operation difficulty is high in practical application, and even if the temperature is accurately controlled, the foaming effect of the open cell polymer foam is still poor.

Through adopting above-mentioned technical scheme, this application places polymer flake in airtight environment, lets in supercritical fluid under certain temperature until the system is saturated, make the crystal area in the polymer completely melt earlier, intensive mixing between each component, then not foam immediately, but cool down the mixture to certain temperature and keep warm 25-35min, with balanced melt strength between each component, the negative effect that phase separation brought has greatly weakened, make the whole mechanical stability of the open-cell polymer foam of final obtain good and each component homoenergetic effectively foam, have higher trompil content and expansion ratio, the foaming temperature interval of this application is wider simultaneously, the operation degree of difficulty is less. Moreover, the open cell content and the expansion ratio of the open cell polymer foam can be further improved by further controlling the system pressure and the cooling temperature, and according to experimental data, the open cell polymer foam prepared in a system with the system pressure of 13.0MPa and the cooling temperature of 132 ℃ has the optimal expansion ratio and open cell content.

In summary, the present application has the following beneficial technical effects:

1. the open-cell polymer foam prepared by the method has the open-cell content not lower than 92.7%, the expansion ratio not lower than 44.30, the average pore diameter not higher than 149.3um, and the maximum stress corresponding to 60% compression ratio not lower than 184KPa, and has good expansion ratio, open-cell content, oil absorption capacity and mechanical stability;

2. the open-cell polymer foam prepared by the method has good oil absorption effect on various oils, wherein the adsorption capacity on gasoline can reach more than 19.52g/g, and the original oil absorption capacity of more than 92.8% is still maintained after 10 times of cyclic adsorption, so that the foam has good rebound performance and recycling property;

3. the preparation method of the open-cell polymer foam is simple and convenient in process, raw materials are easy to obtain, negative effects caused by phase separation are obviously reduced, and the whole mechanical stability of the finally obtained open-cell polymer foam is good, and all components can be effectively foamed.

Drawings

Fig. 1 is an electron microscope scanning micrograph of example 1.3.

Detailed Description

Material source

Except special descriptions, the raw materials used in the application are all commercial products, and are specifically:

n-hexane was purchased from the company He Fang county gold cis chemical Co., ltd;

1. octenes were purchased from Shanghai Ala Biochemical technologies Co., ltd;

ethylene was purchased from Shanghai Ala Biochemical technologies Co., ltd;

antioxidant 1076 is purchased from Nanjing Milan chemical Co., ltd, and has a molecular weight of 531.0;

ferrous bromide was purchased from Shandong polymer chemistry Co., ltd;

propylene-ethylene elastomers were purchased from the biotechnology company of Jixin Yibang, wuhan;

the fully vulcanized thermoplastic rubber is purchased from Kaiwan engineering plastic materials Co., ltd, and the brand is 121-70-M350;

ethylene-methyl acrylate copolymer is purchased from Kaiwan engineering plastics materials Co., ltd, dongguan, trade name 20-MBG-08;

the supercritical fluid is any one of supercritical carbon dioxide and supercritical nitrogen, wherein the supercritical carbon dioxide is purchased from Ningbo Xin Qiti Co., ltd, and the purity is 99.5%;

the high melt strength polypropylene is purchased from Zhenhai refining division of China petrochemical Co., ltd, the melting temperature is 154 ℃, the melt index (2.16 kg@230 ℃) is 1.5g/10min, and the melt strength at 180 ℃ is 0.174N; the melt strength is RHEOTENS 71.97%Ltd, buchen, germany) equipment, the wheel acceleration of the equipment was set at 60mm/s during the test ² The wheel spacing is 0.6mm, linearly increasing along with the rotation speed of the wheel, and recording the maximum force when the fuse breaks until the fuse breaks;

ethylene-butene copolymer (random copolymer of ethylene and 1-butene) was purchased from Shanghai plastic cement Co., ltd, model SK8605L;

ethylene-octene copolymers (random copolymers of ethylene and 1-octene) were purchased from dow, usa and the model and corresponding performance parameters are shown in table 1:

TABLE 1

Model number	Density (g/cm) ³ )	Melt index (g/10 min)	Molar insertion of octene (%)
				8842	0.857	1.0	20.14
8100	0.870	1.0	18.55
				8003	0.885	1.0	10.48
8480	0.902	1.0	6.44
				8450	0.902	3.0	4.86

Wherein the molar insertion rate of octene is measured by high-temperature nuclear magnetic test, the polymer is firstly dissolved in deuterated o-dichlorobenzene at 150 ℃, after the polymer is uniformly dissolved, the polymer is analyzed by nuclear magnetic resonance carbon spectrum, the carbon attribution is distinguished by adopting ASTM D5017-96 standard, the model of the instrument is AVANCENEO 700MHz, the test scanning temperature is 110 ℃, and the pulse angle is set to 90 degrees; density was measured using ASTM D792 standard; melt index (2.16 kg @190 ℃) was measured using ASTM D1238 standard.

Example 1.1

A method of preparing an open cell polymeric foam comprising the steps of:

s1, preparing a polymer sheet: melt blending 90kg of high melt strength polypropylene and 10kg of ethylene-butene copolymer at 170 ℃, extruding the obtained melt into a heating cylinder, simultaneously injecting the melt into a mold with the thickness of 2.0mm by using a matched injection molding machine, wherein the temperature of the injection mold is 60 ℃, the injection pressure is 63.0MPa, and finally obtaining a polymer sheet with the thickness of 2 mm;

s2, preparing an open-cell polymer foam: placing the polymer sheet in a closed reaction kettle, introducing supercritical carbon dioxide into the closed reaction kettle at the temperature of 180 ℃ until the system pressure is 10.0MPa, cooling to 120 ℃, carrying out heat preservation reaction for 35min, opening a reaction kettle valve, and carrying out air exhaust and pressure relief at the pressure relief rate of 100MPa/s to obtain the open-cell polymer foam.

Example 1.2

A method of preparing an open cell polymeric foam comprising the steps of:

s1, preparing a polymer sheet: melt blending 80kg of high melt strength polypropylene and 20kg of ethylene-butene copolymer at 170 ℃, extruding the obtained melt into a heating cylinder, simultaneously injecting the melt into a mold with the thickness of 2.0mm by using a matched injection molding machine, wherein the temperature of the injection mold is 60 ℃, the injection pressure is 63.0MPa, and finally obtaining a polymer sheet with the thickness of 2 mm;

s2, preparing an open-cell polymer foam: placing the polymer sheet in a closed reaction kettle, introducing supercritical carbon dioxide into the closed reaction kettle at 160 ℃ until the system pressure is 20.0MPa, cooling to 137 ℃, carrying out heat preservation reaction for 25min, opening a reaction kettle valve, and carrying out air exhaust and pressure relief at a pressure relief rate of 500MPa/s to obtain the open-cell polymer foam.

Example 1.3

A method of preparing an open cell polymeric foam comprising the steps of:

s1, preparing a polymer sheet: melt blending 70kg of high melt strength polypropylene and 30kg of ethylene-butene copolymer at 170 ℃, extruding the obtained melt into a heating cylinder, simultaneously injecting the melt into a mold with the thickness of 2.0mm by using a matched injection molding machine, wherein the temperature of the injection mold is 60 ℃, the injection pressure is 63.0MPa, and finally obtaining a polymer sheet with the thickness of 2 mm;

s2, preparing an open-cell polymer foam: placing the polymer sheet in a reaction kettle, introducing supercritical carbon dioxide into the reaction kettle at the temperature of 180 ℃ until the system pressure is 13.0MPa, cooling to 132 ℃, carrying out heat preservation reaction for 35min, opening a valve of the reaction kettle, and carrying out air exhaust and pressure relief at the pressure relief rate of 500MPa/s to obtain the open-cell polymer foam.

Example 1.4

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: the high melt strength polypropylene was 90kg, the ethylene-butene copolymer was 10kg, and the remainder was the same as in example 1.3.

Example 1.5

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: 80kg of high melt strength polypropylene and 20kg of ethylene-butene copolymer were obtained, and the remainder was the same as in example 1.3.

Example 1.6

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: the high melt strength polypropylene was 60kg, the ethylene-butene copolymer was 40kg, and the remainder was the same as in example 1.3.

Comparative example 1

s2, preparing an open-cell polymer foam: placing the polymer sheet in a reaction kettle, introducing supercritical carbon dioxide into the reaction kettle at the temperature of 154 ℃ until the system pressure is 13.0MPa, then opening a valve of the reaction kettle, and exhausting and decompressing at the decompression rate of 500MPa/s to obtain the open-cell polymer foam.

Comparative example 2

S1, preparing a polymer sheet: melting 100kg of high-melt-strength polypropylene at 170 ℃, extruding the obtained melt into a heating cylinder, simultaneously injecting the melt into a mold with the thickness of 2.0mm by using a matched injection molding machine, wherein the temperature of the injection mold is 60 ℃, the injection pressure is 63.0MPa, and finally obtaining a polymer sheet with the thickness of 2 mm;

s2, preparing an open-cell polymer foam: placing the polymer sheet in a reaction kettle, introducing supercritical carbon dioxide into the reaction kettle at 156 ℃ until the system pressure is 13.0MPa, cooling to 132 ℃, carrying out heat preservation reaction for 35min, opening a valve of the reaction kettle, and carrying out air exhaust and pressure relief at a pressure relief rate of 500MPa/s to obtain the open-cell polymer foam.

Comparative example 3

The difference from example 1.3 is that: the ethylene-butene copolymer was 50kg, the high melt strength polypropylene was 50kg, and the remainder was the same as in example 1.3.

Comparative example 4

The difference from example 1.3 is that: the ethylene-butene copolymer was replaced with a fully vulcanized thermoplastic rubber, and the rest was the same as in example 1.3.

Comparative example 5

The difference from example 1.3 is that: the ethylene-butene copolymer was replaced with an ethylene-methyl acrylate copolymer, and the rest was the same as in example 1.3.

Comparative example 6

The difference from example 1.3 is that: in step S2, the pressure release rate was 60MPa/S, and the rest was the same as in example 1.3.

Performance detection

The ear polymer foams prepared in examples 1.1 to 1.6 and comparative examples 1 to 6 were examined as follows:

1. the Open Cell Content (OCC) of the polymer foam was measured with a gas displacement density analyzer:

OCC＝{(V _open /V _total )×100％+[1-(V _ture /V _total )]x 100% } 2, where V _open 、V _ture And V _total The data are recorded in table 2 for open cell volume, true volume (including closed cell volume and cell wall volume) and total volume of the foam, respectively;

2. referring to the method in GB/T8813-2008, the compression properties of open-cell polymer foams were measured and the corresponding maximum stress at a compression ratio of 60% was recorded in table 2;

3. the mass density (. Rho.) of the open-cell polymer foam samples before foaming was determined by the water displacement method, with reference to the method in ISO1183-1987 _v ) And the mass density after foaming (ρ) _f ) The method comprises the steps of carrying out a first treatment on the surface of the The Expansion Ratio (ER) of a foam can be calculated by the formula: er=ρ _v /ρ _f Samples prepared under the same conditions were tested at least three times and the average value was calculated and the data recorded in table 2;

4. oil absorption capacity detection:

(1) single oil adsorption: the open-cell polymer foam was first weighed and then immersed in a beaker containing 100ml of petrol, after adsorption for 0.5h, the foam was removed from the oil and weighed rapidly, oil absorption capacity (g/g) = (m _s -m ₀ )/m ₀ ；

Wherein m is ₀ For drying the weight of the open-cell foam sample, m _s The weight of the open-cell foam sample after saturation for adsorption of the target oil;

(2) and (3) circulating oil adsorption: immersing the foam in the absorbed oil until reaching saturated weight, then extruding the oil in the foam as much as possible, absorbing oil again and repeating the operation for 9 times more, obtaining the cyclic oil absorption capacity = [ (m) ₁₀ -m ₀ )/m ₀ ]Record data in table 2;

5. average pore size calculation: estimating the average aperture by the scaling in the scanning electron microscope photograph after scanning electron microscopy of the sample, and recording the result in table 2;

6. soaking the prepared sample in liquid nitrogen for 3-5min, then brittle breaking, and then spraying metal in a vacuum chamber, and shooting the cross section of the sample by adopting a Hitachi TM300 scanning electron microscope.

TABLE 2

Connect table 2

Analysis of the data in table 2:

the OCC of the embodiment 1.1-1.6 can reach 92.7-95.0%, the corresponding maximum stress at 60% compression ratio can reach 184-228KPa, ER can reach 44.30-45.40, the single oil absorption capacity can reach 19.52-20.00g/g, the cyclic oil absorption capacity can reach 19.44-18.56g/g, 92.8% of the original oil absorption capacity is still maintained after 10 cycles of absorption of gasoline, the average pore diameter can reach 145.7-149.3um, wherein the scanning microscope photograph of the embodiment 1.3 is shown in figure 1, and the scanning microscope photographs of other embodiments are similar to the scanning microscope photograph, so that the open-cell polymer foam prepared by the application has good open cell content, oil absorption performance, rebound performance, mechanical stability and oil-water selectivity.

The ethylene-1-butene copolymer of examples 1.4, 1.5 and 1.3, which are parts by weight of the total mass, are sequentially increased, the OCC, ER and oil absorption capacity are also increased, and the average pore diameter is reduced, so that the ethylene-1-butene copolymer can effectively improve the aperture ratio, the oil absorption performance, the rebound resilience performance and the oil-water selectivity of the open-cell polymer foam; according to experimental data, the single oil absorption capacity and the cyclic oil absorption of the embodiment 1.3 are higher than those of the embodiment 1.4-1.5, and the ethylene-1-butene copolymer in the embodiment 1.6 accounts for more than the embodiment 1.3 in parts by weight of the total mass, and as the ethylene-1-butene copolymer brings certain reduction of mechanical stability, various performance parameters of the ethylene-1-butene copolymer are slightly reduced compared with those of the embodiment 1.3, the oil absorption performance and the rebound resilience of the open-cell polymer foam are effectively balanced by further limiting the weight ratio range of the high melt strength polypropylene to the ethylene-1-butene copolymer;

the performance parameters of comparative example 1 are far worse than those of example 1.3, and the application proves that the two-step foaming method adopted by the application achieves the effects of balancing the melt strength among the components and weakening the negative influence caused by phase separation, so that the finally obtained open-cell polymer foam has good aperture ratio, oil absorption performance, rebound performance, mechanical stability and oil-water selectivity;

the performance parameters of comparative example 2 are far lower than those of example 1.3 except the maximum stress, and the fact that the open porosity, oil absorption performance, rebound resilience performance and oil-water selectivity of the open-cell polymer foam are effectively improved after the polyolefin elastomer is doped into the high melt strength polypropylene in the application is proved;

the performance parameters of comparative example 3 are far lower than those of example 1.3, further demonstrating that the oil absorption performance and rebound resilience performance of the open cell polymer foam can be effectively balanced by controlling the weight ratio range of the high melt strength polypropylene to the ethylene-1-butene copolymer;

the performance parameters of comparative examples 4-5, except for the maximum stress, are much lower than those of example 1.3, demonstrating that the application uses a polyolefin elastomer with good compatibility with high melt strength polypropylene to improve the oil absorption and rebound properties of the open cell polymer foam optimally compared with other elastomers;

both OCC and ER of comparative example 6 were much lower than example 1.3, demonstrating that when the pressure release rate was below the rate range specified in this application, the molten mixture failed to effectively foam in cell expansion, severely affecting the open cell content and oil absorption properties.

Example 2.1

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the cooling temperature was 123℃and the same as in example 1.3 was repeated.

Example 2.2

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the cooling temperature was 127℃and the same as in example 1.3 was repeated.

Example 2.3

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the cooling temperature was 133℃and the same as in example 1.3 was repeated.

Example 2.4

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the cooling temperature was 135℃and the same as in example 1.3 was repeated.

Example 2.5

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the cooling temperature was 137℃and the same as in example 1.3 was repeated.

Performance detection

The performance measurements were performed according to the test methods described above for examples 2.1-2.5, and the results are recorded in Table 3.

TABLE 3 Table 3

Group of	OCC/％	Maximum stress/KPa	ER
				Example 1.3	95.0	222	45.40
Example 2.1	93.6	231	44.73
				Example 2.2	93.8	227	44.83
Example 2.3	94.1	219	44.97
				Example 2.4	93.5	214	44.68
Example 2.5	92.9	208	44.40

Connect table 3

Group of	Single oil absorption capacity g/g	Oil absorption capacity g/g	Average pore size/um
				Example 1.3	20.00	18.56	145.70
Example 2.1	19.71	18.26	147.88
				Example 2.2	19.75	17.99	147.56
Example 2.3	19.81	17.41	147.09
				Example 2.4	19.68	16.90	148.04
Example 2.5	19.56	16.32	148.99

Analysis of the data in table 3:

comparing examples 1.3 and 2.1-2.5 longitudinally, it can be seen that under the condition of cooling temperature of 120-137 ℃, OCC can reach 92.9-95.0%, maximum stress corresponding to 60% compression ratio can reach 208-231KPa, ER can reach 44.40-45.40, single oil absorption capacity can reach 19.56-20.00g/g, circulating oil absorption capacity can reach 16.32-18.56g/g, original oil absorption capacity of 92.8% is still maintained after 10 cycles of absorption of gasoline, average pore diameter is 145.70-148.99um, and it is proved that the open-cell polymer foam prepared under the cooling temperature range defined by the application has good aperture ratio, oil absorption performance, rebound performance, mechanical stability and oil-water selectivity;

as the cooling temperature rises from 120 ℃ to 137 ℃, the variation trend of the OCC and ER gradually rises and then falls at the inflection point (132 ℃), the ER, OCC, oil absorption capacity and average pore diameter at 132 ℃ are all the best data, and the 132 ℃ becomes the best foaming temperature, so that the oil absorption performance and rebound performance of the open-cell polymer foam are well balanced.

Example 3.1

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the system pressure was 10MPa, and the other steps were the same as in example 1.3.

Example 3.2

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the system pressure was 15MPa, and the other steps were the same as in example 1.3.

Example 3.3

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the system pressure was 17MPa, and the same as in example 1.3 was found.

Example 3.4

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in step S2, the system pressure was 20MPa, and the other steps were the same as in example 1.3.

Performance detection

The performance measurements were performed according to the test methods described above for examples 3.1-3.4, and the results are recorded in Table 4.

TABLE 4 Table 4

Group of	OCC/％	Maximum stress/KPa	ER
				Example 1.3	95.0	222	45.40
Example 3.1	93.5	231	44.68
				Example 3.2	93.7	220	44.78
Examples3.3	93.2	216	44.54
				Example 3.4	92.5	210	44.21

Connect table 4

Group of	Single oil absorption capacity g/g	Oil absorption capacity g/g	Average pore size/um
				Example 1.3	20.00	18.56	145.70
Example 3.1	19.68	18.59	148.04
				Example 3.2	19.73	17.74	147.72
Example 3.3	19.62	17.33	148.51
				Example 3.4	19.47	16.72	149.64

Analysis of the data in table 4:

the longitudinal comparison of examples 1.3 and examples 2.1-2.5 shows that under the condition of 10-20MPa of system pressure, OCC can reach 92.5-95.0%, the corresponding maximum stress at 60% compression ratio can reach 210-231KPa, ER can reach 44.21-45.40, the single oil absorption capacity can reach 19.47-20.00g/g, the circulating oil absorption capacity can reach 16.72-18.56g/g, 92.8% of original oil absorption capacity is still maintained after 10 cycles of absorption of gasoline, the average pore diameter is 145.70-149.64um, and the open-cell polymer foam prepared under the system pressure range defined by the application has good aperture ratio, oil absorption performance, rebound performance, mechanical stability and oil-water selectivity;

as the system pressure rises from 10MPa to 20MPa, the change trend of OCC and ER gradually rises and then falls at the inflection point (13 MPa), the ER, OCC, oil absorption capacity and average pore diameter at 13MPa are all the best data, and 13MPa becomes the best foaming temperature, so that the oil absorption performance and rebound performance of the open-cell polymer foam are well balanced.

Examples 4.1 to 4.5

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: the ethylene-butene copolymer was replaced with a different type of ethylene-octene copolymer, respectively, all of which were the same as in example 1.3; wherein the ethylene-octene copolymer of example 4.1 is model 8003; the ethylene-octene copolymer type number of example 4.2 is 8100; the ethylene-octene copolymer of example 4.3 is model 8842; the ethylene-octene copolymer of example 4.4 is model 8480; the ethylene-octene copolymer of example 4.5 was model 8450.

Performance detection

The performance measurements were performed according to the test methods described above for examples 4.1-4.5, and the results are recorded in Table 5.

TABLE 5

Group of	OCC/％	Maximum stress/KPa	ER
				Example 1.3	95.0	220	45.40
Example 4.1	96.9	227	46.31
				Example 4.2	97.6	229	48.00
Example 4.3	96.1	222	45.48
				Example 4.4	95.4	227	45.59
Example 4.5	95.0	230	45.40

Connect table 5

Group of	Single oil absorption capacity g/g	Oil absorption capacity g/g	Average pore size/um
				Example 1.3	20.00	18.56	145.70
Example 4.1	20.40	18.93	142.84
				Example 4.2	21.01	19.47	142.40
Example 4.3	20.18	18.63	144.99
				Example 4.4	20.08	18.64	145.09
Example 4.5	20.00	17.99	145.70

Analysis of the data in table 5:

in examples 4.1-4.5, the OCC can reach 95.0-97.6%, the corresponding maximum stress can reach 222-230KPa at 60% compression ratio, ER can reach 45.40-48.00, the single oil absorption capacity can reach 20.00-21.01g/g, the cyclic oil absorption capacity can reach 17.99-19.47g/g, the average pore diameter is 142.40-145.70um, and the overall performance is better than that of example 1.3, so that the ethylene-butene copolymer is proved to be replaced by the ethylene-octene copolymer, the moderate chain length of octene is utilized, the compatibility of high melt strength polypropylene and the ethylene-octene copolymer is higher, and the aperture ratio, the oil absorption performance and the oil-water selectivity of the open-cell polymer foam are further improved; the combination property of the examples 4.1-4.5 and the examples 4.1-4.2 is better than that of the examples 4.3-4.5, and the fact that the oil absorption performance, the rebound performance, the oil-water selectivity and the mechanical stability of the open-cell polymer foam can be effectively improved through the limited octene molar insertion rate of the ethylene-octene copolymer is proved; wherein the properties of example 4.2 are optimal.

Example 5.1

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in S1, 0.35kg of a propylene-ethylene elastomer was also added to the system, and the same as in example 1.3 was carried out.

Example 5.2

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in S1, 0.56kg of a propylene-ethylene elastomer was also added to the system, and the same as in example 1.3 was repeated.

Example 5.3

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in S1, 0.21kg of a propylene-ethylene elastomer was also added to the system, and the same as in example 1.3 was carried out.

Example 5.4

A process for the preparation of an open-cell polymer foam, which differs from example 1.3 in that: in S1, 0.70kg of a propylene-ethylene elastomer was also added to the system, and the same as in example 1.3 was carried out.

Performance detection

The performance measurements were performed according to the test methods described above for examples 5.1-5.4, and the results are recorded in Table 6.

TABLE 6

Group of	OCC/％	Maximum stress/KPa	ER
				Example 1.3	95.0	220	45.40
Example 5.1	98.6	231	48.64
				Example 5.2	99.3	235	50.16
Example 5.3	98.3	231	47.50
				Example 5.4	98.7	232	48.69

Connect table 6

Group of	Single oil absorption capacity g/g	Oil absorption capacity g/g	Average pore size/um
				Example 1.3	20.00	18.56	145.70
Example 5.1	22.05	20.62	141.82
				Example 5.2	23.07	21.73	141.67
Example 5.3	21.99	20.39	142.26
				Example 5.4	22.07	20.73	141.67

Analysis of the data in table 6:

in examples 5.1-5.4, OCC can reach 98.3-99.3wt%, the corresponding maximum stress can reach 231-235KPa at 60% compression ratio, ER can reach 47.50-50.16, the single oil absorption capacity can reach 21.99-23.07g/g, the cyclic oil absorption capacity can reach 20.39-21.73g/g, the average pore diameter is 141.67-142.26um, and the overall performance is better than that of example 1.3, and the propylene-ethylene elastomer is added into the raw materials, so that the combination degree and compatibility among the components are obviously optimized, and the oil absorption performance, rebound performance, oil-water selectivity and mechanical stability of the open-cell foam composite material are further improved;

longitudinal comparison of examples 5.1-5.4 demonstrates that the present application avoids increasing unnecessary production costs by controlling the amount of propylene-ethylene elastomer added, while ensuring effective optimization of the open cell polymer foam with good oil absorption and rebound properties.

Applicability detection

The open cell polymer foam samples prepared in comparative example 1 and example 1.3, example 4.2 and example 5.2 were cut into rectangles having a length of about 2cm, respectively, and subjected to the following series of performance tests, in particular, as follows:

1. and (3) oil-water selectivity detection: a mixed solvent composed of cyclohexane (which has been labeled with sudan red) and water was poured into a container, and an open-cell polymer foam was used as a filter for the mixed solvent, and after completion of the filtration process, the color transition of the mixed solvent was observed, and the results are recorded in table 7:

poor-no discoloration; general-no obvious discoloration; good-has obvious discoloration; excellent-complete color change; 2. oil absorption performance detection of different oils: the open cell polymer foam was immersed in cyclohexane, carbon tetrachloride, octane and sunflower oil respectively and adsorbed, and its oil absorption capacity was recorded respectively, and the data are recorded in table 7.

TABLE 7

Analysis of the data in table 7:

the oil-water selectivity of examples 1.3, 4.2 and 5.2 was far better than that of comparative example 1, and after filtration, the liquid entering the Erlenmeyer flask had changed significantly from red to colorless, indicating that the open cell polymer foam absorbed sudan red labeled cyclohexane, while water flowed into the flask through the open cell structure within the foam. And examples 1.3, 4.2 and 5.2 have good adsorption capacities to various oils, which fully demonstrate that the open-cell polymer foam prepared by mixing a polyolefin elastomer with high melt strength polypropylene according to a certain proportion and foaming the mixture under the condition of two-step foaming has excellent oil absorption performance and oil-water selectivity.

The embodiments of the present invention are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in this way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims

1. An open cell polymeric foam characterized by: the raw materials used comprise high melt strength polypropylene and polyolefin elastomer with the weight ratio of (6-9) to (1-4).

2. An open cell polymeric foam according to claim 1, wherein: the weight ratio of the high melt strength polypropylene to the polyolefin elastomer is (6-7) to (3-4).

3. An open cell polymeric foam according to claim 2, wherein: the weight ratio of the high melt strength polypropylene to the polyolefin elastomer is 7:3.

4. An open cell polymer foam according to any one of claims 1-3, characterized in that: the polyolefin elastomer is an ethylene-octene copolymer.

5. An open cell polymeric foam according to claim 4, wherein: the ethylene-octene copolymer has an octene molar insertion of 10.48-18.55% and a melt index of 1.0g/min.

6. An open cell polymeric foam according to claim 5, wherein: the molar insertion of octene of the ethylene-octene copolymer was 18.55%.

7. An open cell polymeric foam according to claim 1, wherein: the raw materials also comprise propylene-ethylene elastomer, wherein the amount of the propylene-ethylene elastomer is 5-8wt% of the amount of the high melt strength polypropylene.

8. A process for the preparation of an open cell polymer foam according to any one of claims 1 to 7, comprising the steps of:

s2, preparing an open-cell polymer foam: placing the polymer sheet in a closed environment, introducing supercritical fluid into the closed environment at 160-180 ℃ until the system pressure is 10.0-20.0MPa, cooling to 120-137 ℃, reacting for 25-35min under heat preservation, and then venting and decompressing at a decompression rate of 100-500MPa/s to obtain the open-cell polymer foam.

9. The method of preparing an open cell polymeric foam according to claim 8, wherein: in the step S2, the system pressure is 13.0MPa, and the cooling temperature is 132 ℃.