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WO1999025530A1 - Mise a l'echelle de mousses a coefficient de poisson negatif - Google Patents

Mise a l'echelle de mousses a coefficient de poisson negatif Download PDF

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Publication number
WO1999025530A1
WO1999025530A1 PCT/US1998/024485 US9824485W WO9925530A1 WO 1999025530 A1 WO1999025530 A1 WO 1999025530A1 US 9824485 W US9824485 W US 9824485W WO 9925530 A1 WO9925530 A1 WO 9925530A1
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WO
WIPO (PCT)
Prior art keywords
foam piece
foam
mold
ratio
pair
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1998/024485
Other languages
English (en)
Inventor
Roderic S. Lakes
Marco A. Loureiro
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wisconsin Alumni Research Foundation
Original Assignee
Wisconsin Alumni Research Foundation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wisconsin Alumni Research Foundation filed Critical Wisconsin Alumni Research Foundation
Priority to AU14617/99A priority Critical patent/AU1461799A/en
Publication of WO1999025530A1 publication Critical patent/WO1999025530A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/35—Component parts; Details or accessories
    • B29C44/355—Characteristics of the foam, e.g. having particular surface properties or structure
    • B29C44/357—Auxetic foams, i.e. material with negative Poisson ratio; anti rubber; dilatational; re-entrant
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/56—After-treatment of articles, e.g. for altering the shape
    • B29C44/5627—After-treatment of articles, e.g. for altering the shape by mechanical deformation, e.g. crushing, embossing, stretching
    • B29C44/5636—After-treatment of articles, e.g. for altering the shape by mechanical deformation, e.g. crushing, embossing, stretching with the addition of heat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
    • B29K2105/045—Condition, form or state of moulded material or of the material to be shaped cellular or porous with open cells

Definitions

  • This disclosure concerns an invention relating generally to negative Poisson's ratio foams, and more specifically to a method of producing such foams in sizes useful for commercial applications.
  • Poisson's ratio is defined as the negative lateral strain of a body divided by its longitudinal strain. Poisson's ratio is dimensionless, and for most solids its value is positive and ranges between 0.25 and 0.33. For most solid foam materials (e.g. , polyurethane foams), Poisson's ratio is about 0.3. However, rubbery materials can have values close to 0.5. Cork, in contrast, is a cellular solid with a Poisson's ratio close to zero.
  • Non-affine (locally inhomogeneous) unfolding of the re-entrant structure is the causal mechanism responsible for the negative Poisson's ratio in these materials.
  • other negative Poisson's ratio materials were identified, including certain microcellular foams, hierarchical laminates, chiral lattices, ⁇ -cristobalite, and closed cell polymer foams.
  • the Poisson's ratios for the foams identified over the last decade can be as low as -0.7 for re-entrant polymer foams, and -0.8 for reentrant metal foams.
  • the foam samples would often experience tearing, particularly at their edges, which rendered them unsuitable for use. Further, it was found that as the compressed foam samples grew larger, the foams resulting after heating had more irregular properties, with the Poisson's ratio varying widely within their volumes (often into the positive range).
  • foam having a negative Poisson's ratio is produced by placing the foam within a mold, compressing the foam by moving the interior walls of the mold inwardly, heating the foam under compression until it is in a softened state wherein re-entrant foam cells form, and then cooling the foam under compression so that the cells set in their re-entrant configuration.
  • the mold can effectively be expanded to accommodate large pieces of foam and can then be collapsed upon (or assembled around) the foam to compress it.
  • the foam is triaxially compressed by moving the interior mold walls inwardly in each of its three orthogonal dimensions. This is beneficially done by subjecting the foam to a substantially equal percentage of compression in all dimensions, i.e. , by applying the same percentage of reduction to each of the length, width, and height dimensions. It is recommended that prior to compressing the foam, lubricant should be applied between the foam and the mold walls.
  • the invention can produce foam pieces having substantially uniform negative
  • the collapsible mold allows triaxial compression to be uniformly applied throughout the entire volume of large foam pieces (i.e.. compression is uniform along each dimension of the foam), particularly where the aforementioned lubrication is used. This has been found to result in Poisson's ratios which are both negative and substantially uniform throughout the foam piece, characteristics that were lacking when the prior Lakes and other methods were extended to larger foam pieces.
  • the methods of the present invention have been found capable of generating pieces of negative Poisson's ratio foam of sufficient size that they can be used as seat cushions or the like.
  • Sample cushions having (unstressed) dimensions of 10 cm x 26 cm x 53 cm have been prepared, and it is expected that the methods described herein could be used to make even larger specimens if desired.
  • FIG. 1 is a perspective view of an idealized conventional (positive Poisson's ratio) tetrakaidecahedron foam cell.
  • FIG. 2 is a perspective view of an idealized re-entrant (negative Poisson's ratio) tetrakaidecahedron foam cell.
  • FIG. 3 is a perspective view of an exemplary mold suitable for use in the present invention.
  • FIG. 4 shows Poisson's ratio vs. axial compressive strain for conventional foam.
  • FIG. 5 shows Poisson's ratio vs. axial compressive strain for conventional foam after 20 minutes of processing towards a re-entrant state, for several values of permanent volumetric compression.
  • FIG. 6 shows Poisson's ratio vs. axial compressive strain for conventional foam after 40 minutes of processing towards a re-entrant state, for several values of permanent volumetric compression.
  • FIG. 7 shows Poisson's ratio vs. axial compressive strain for conventional foam after 60 minutes of processing towards a re-entrant state, for several values of permanent volumetric compression.
  • FIG. 8 shows compressive stress-strain curves for conventional and re-entrant foams.
  • FIG. 3 illustrates an exemplary mold 10 used in the methods of the present invention.
  • the mold 10 includes five wall members 12, 14, 16, 18, and 20, wherein each wall member provides a single internal mold wall except for wall component 20, which provides two mold walls 22 and 24.
  • the mold 10 is adapted to accommodate a conventional piece of foam between its wall members, which may then be assembled about the foam piece to compress it along its different axes in sequence. As an example, one might initially place the foam piece on wall 22 of wall component 20, and then push wall component 18 towards wall 24 of wall component 20 until they leave just so much space therebetween that wall members 14 and 16 may be inserted. Wall members 14 and 16 may then be pushed inwardly, and finally wall component 12 may be moved inwardly towards wall 22 of wall component 20.
  • the internal dimensions of the mold 10 are adjustable in three dimensions so as to allow expansion of the mold's interior to accommodate a large piece of foam, and the mold may then be assembled around or collapsed upon the foam piece to provide triaxial compression of the entirety of the foam piece resting therein.
  • Other types of molds may also be used to provide triaxial compression while at the same time allowing foam pieces to be easily inserted and removed; for example, wall component 20 could be affixed to wall component 14 so that the interior of the mold 10 would be defined by four wall components 12, 16,
  • wall component 20 could be severed between mold walls 22 and 24 so that six separate wall components are provided.
  • the mold 10 Prior to insertion of foam within the mold 10, it is preferable to first lubricate its wall members 12, 14, 16, 18, and 20 so as to prevent the foam inserted therein from sticking to the wall members. If localized sticking (or sticking along an entire face of the foam piece) occurs, this could give rise to nonuniform compression of the foam, and thus nonuniform generation of re-entrant cell structure and nonuniform Poisson's ratio. In contrast, if friction is minimized between the wall members and the foam, compression should be relatively uniform along all axes. After the mold 10 is used to place the foam sample into triaxial compression, the mold 10 can be heated for appropriate times at appropriate temperatures to process the conventional foam into a re-entrant form.
  • foams tend to be thermal insulators, and thus molds having the shape shown in FIG. 3 (wherein one dimension is relatively small with respect to the others) might allow lesser processing times since heat will transfer to the center of the foam relatively rapidly along the short dimension.
  • molds having the shape shown in FIG. 3 might allow lesser processing times since heat will transfer to the center of the foam relatively rapidly along the short dimension.
  • dimensions of the foam grow larger and/or substantially even in all dimensions — i.e.
  • Poisson's ratio for the conventional foam is plotted in FIG. 4 as a function of the compressive longitudinal strain. At small strain, Poisson's ratio has a value near 0.3 , and it approaches zero as more compression is applied.
  • a stress/strain plot for the conventional foam (as received) is also illustrated in FIG. 8, where it can be seen that Young's modulus E (the ratio of tension stress along an object's axis to the resulting strain along the same axis in the linear stress/strain region) was 9.3 kPa. Above the linear region, a "plateau" region of reduced slope was observed.
  • Young's modulus is of interest because the lateral strain in a body subjected to longitudinal loading is equal to the negative product of Poisson's ratio and the longitudinal stress, divided by Young's modulus. Hence, Poisson's ratio and Young's modulus together define the interrelationship of stress and strain along a body's various axes.
  • the mold used in the experiments has the same approximate configuration as the mold of FIG. 3, and was made of aluminum for good heat transfer.
  • the major surfaces of the wall members 10/20, 14/16, and 18 respectively measured 43.2 x 21 centimeters, 43.2 x 8.3 centimeters, and 21 x 8.3 centimeters.
  • the mold walls were 1.3 millimeters thick, which is stiff enough to resist bending or bulging when the aforementioned ultra-max foam specimens are compressed.
  • Ordinary vegetable oil was used as a mold lubricant, and was found to help eliminate wrinkles that otherwise occurred when compressing the foam. Since wrinkles spaced along a length of the foam indicate nonuniform compression along that axis, their elimination during compression was evidence that substantially uniform compression was being obtained.
  • the furnace was first preheated to a desired temperature.
  • the mold was placed in the furnace for the noted times, and was then removed and allowed to cool at room temperature.
  • Poisson's ratio was measured as follows. Fiduciary marks were made on the foam specimen. One side of the specimen was placed against a flat vertical surface while the opposite side was uniformly compressed with the aid of a steel plate. Deformation was measured with a calibrated scale, which provided sufficient resolution (0.8mm) in view of the large size of the specimens. Poisson's ratios were measured based on compression in the longest direction of each specimen and transverse deformation in the second longest direction. In the tables, the given Poisson's ratio value is expressed as a maximum magnitude for the specific compressive longitudinal strain.
  • FIGS. 3-8 graphically illustrate the results of TABLES 2, 3 and 4 below, and show the variation of Poisson's ratio as a function of strain for foam specimens processed under different conditions. Curves are fitted via cubic polynomials. The results for each of the processing conditions will now be individually discussed.
  • TABLE 2 illustrates the results for conventional foam processed for 20 minutes — a processing condition referred to as Series 1 — and FIG. 5 illustrates Poisson's ratio as a function of compressive longitudinal strain for these samples.
  • the analysis also considered the recovery aspect of the foam blocks after transformation.
  • the Series 1 specimens recovered, on an average, 16.5 % of their initial volume, which suggests a high recovery when compared to the 2.7 % recovery observed for specimens of Series 2 (discussed below). Young's modulus was 6.2 kPa for the foam with the greatest volumetric compression in this series. In these results the specimens did not achieve re-entrant characteristics, a fact which suggests that the heating time was insufficient.
  • These partially transformed specimens exhibited irregular behavior of Poisson's ratio versus compressive longitudinal strain.
  • FIG. 8 compares the resilience of the transformed blocks to that of the conventional foam which, in common with other polymer foams, shows a change in slope near 5 % strain.
  • the present ultra-max foam exhibited an increase in Young's modulus with processing, in contrast with prior results for Scott Industrial foam having relatively uniform cell size, in which Young's modulus decreased with processing. The difference is believed to arise from the more irregular cell sizes and structures in the ultra-max foams as compared to the Scott Industrial foams of the prior experiments.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

L'invention concerne des morceaux de mousse présentant un coefficient de Poisson négatif et des volumes de l'ordre de quelques milliers de centimètres cube. Ces morceaux de mousse peuvent être préparés par l'assemblage autour d'un morceau de mousse, par exemple de la mousse standard de polyuréthanne à alvéoles ouverts, d'un moule (10) présentant des parois (12, 14, 16, 18 et 20) de manière à comprimer la mousse dans les trois dimensions. Pendant la compression, la mousse est chauffée jusqu'à atteindre un état plastique ou semi-plastique, puis refroidie, ce refroidissement amenant les alvéoles de la mousse à prendre des configurations rentrantes.
PCT/US1998/024485 1997-11-19 1998-11-16 Mise a l'echelle de mousses a coefficient de poisson negatif Ceased WO1999025530A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU14617/99A AU1461799A (en) 1997-11-19 1998-11-16 Scale-up of negative poisson's ratio foams

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6548797P 1997-11-19 1997-11-19
US60/065,487 1997-11-19

Publications (1)

Publication Number Publication Date
WO1999025530A1 true WO1999025530A1 (fr) 1999-05-27

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007052054A1 (fr) * 2005-11-04 2007-05-10 Auxetic Technologies Limited Procede de fabrication de mousses auxetiques
CN100503703C (zh) * 2005-12-21 2009-06-24 中国科学院化学研究所 负泊松比材料及其制备方法和用途
GB2464947A (en) * 2008-10-29 2010-05-05 Global Composites Group Ltd Auxetic foam manufacturing system
DE102008043623A1 (de) 2008-11-10 2010-05-12 Friedrich-Alexander-Universität Erlangen-Nürnberg Auxetisches Material
EP2319674A1 (fr) 2009-11-06 2011-05-11 Rolls-Royce Plc Procédé de fabrication de mousse
WO2011090588A2 (fr) 2009-12-30 2011-07-28 3M Innovative Properties Company Procédé une fabrication d'une maille auxétique
WO2011090587A2 (fr) 2009-12-30 2011-07-28 3M Innovative Properties Company Treillis auxétique moulé
US8388248B2 (en) 2008-12-30 2013-03-05 Kimberly-Clark Worldwide, Inc. Medical liquid applicator system
US8967147B2 (en) 2009-12-30 2015-03-03 3M Innovative Properties Company Filtering face-piece respirator having an auxetic mesh in the mask body
EP2865504A1 (fr) * 2013-10-14 2015-04-29 Rolls-Royce plc Procédé de fabrication d'une mousse présentant un coefficient de Poisson dont le gradient varie d'une valeur négative à une valeur positive
EP2865505A1 (fr) * 2013-10-14 2015-04-29 Rolls-Royce plc Procédé de fabrication d'une mousse présentant un comportement de coefficient de poisson à gradient
CN105001622A (zh) * 2015-07-29 2015-10-28 国家纳米科学中心 一种负泊松比多功能海绵及其制备方法
WO2016014782A1 (fr) * 2014-07-25 2016-01-28 The Florida State University Research Foundation, Inc. Systèmes de matériaux et procédés de fabrication pour des mousses auxétiques
WO2018213590A1 (fr) 2017-05-18 2018-11-22 Auxadyne, Llc Procédé et appareil destinés à produire une mousse auxétique
WO2019053143A1 (fr) * 2017-09-13 2019-03-21 Basf Se Mousses auxétiques de polyuréthane et de mélamine par compression triaxiale
CN109722558A (zh) * 2019-01-14 2019-05-07 南京航空航天大学 一种具有负泊松比特性的闭孔泡沫铝材料的熔体发泡制备方法
CN112512772A (zh) * 2018-05-31 2021-03-16 耐克创新有限合伙公司 用于鞋类物品的缓冲构件及相关方法
CN113980346A (zh) * 2021-10-29 2022-01-28 中国科学院长春应用化学研究所 一种开孔聚氨酯负泊松比泡沫材料及其制备方法
US12123470B1 (en) * 2020-07-15 2024-10-22 United States Of America As Represented By Secretary Of The Air Force Flexible multi-material structures

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US5108413A (en) * 1990-12-20 1992-04-28 Moyers Robert E Dilator for opening the lumen of a tubular organ
US5334903A (en) * 1992-12-04 1994-08-02 The United States Of America As Represented By The Secretary Of The Navy Composite piezoelectrics utilizing a negative Poisson ratio polymer

Patent Citations (4)

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US4668557A (en) * 1986-07-18 1987-05-26 The University Of Iowa Research Foundation Polyhedron cell structure and method of making same
US5035713A (en) * 1990-02-12 1991-07-30 Orthopaedic Research Institute, Inc. Surgical implants incorporating re-entrant material
US5108413A (en) * 1990-12-20 1992-04-28 Moyers Robert E Dilator for opening the lumen of a tubular organ
US5334903A (en) * 1992-12-04 1994-08-02 The United States Of America As Represented By The Secretary Of The Navy Composite piezoelectrics utilizing a negative Poisson ratio polymer

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007052054A1 (fr) * 2005-11-04 2007-05-10 Auxetic Technologies Limited Procede de fabrication de mousses auxetiques
CN100503703C (zh) * 2005-12-21 2009-06-24 中国科学院化学研究所 负泊松比材料及其制备方法和用途
GB2464947A (en) * 2008-10-29 2010-05-05 Global Composites Group Ltd Auxetic foam manufacturing system
DE102008043623A1 (de) 2008-11-10 2010-05-12 Friedrich-Alexander-Universität Erlangen-Nürnberg Auxetisches Material
US8388248B2 (en) 2008-12-30 2013-03-05 Kimberly-Clark Worldwide, Inc. Medical liquid applicator system
EP2319674A1 (fr) 2009-11-06 2011-05-11 Rolls-Royce Plc Procédé de fabrication de mousse
US8313682B2 (en) 2009-11-06 2012-11-20 Rolls-Royce Plc Method of manufacturing a foam
WO2011090588A2 (fr) 2009-12-30 2011-07-28 3M Innovative Properties Company Procédé une fabrication d'une maille auxétique
WO2011090587A2 (fr) 2009-12-30 2011-07-28 3M Innovative Properties Company Treillis auxétique moulé
US8728369B2 (en) 2009-12-30 2014-05-20 3M Innovative Properties Company Method of making an auxetic mesh
US8967147B2 (en) 2009-12-30 2015-03-03 3M Innovative Properties Company Filtering face-piece respirator having an auxetic mesh in the mask body
US9956729B2 (en) 2013-10-14 2018-05-01 Rolls-Royce Plc Method of manufacturing a foam showing a gradient poisson's ratio behaviour
EP2865504A1 (fr) * 2013-10-14 2015-04-29 Rolls-Royce plc Procédé de fabrication d'une mousse présentant un coefficient de Poisson dont le gradient varie d'une valeur négative à une valeur positive
EP2865505A1 (fr) * 2013-10-14 2015-04-29 Rolls-Royce plc Procédé de fabrication d'une mousse présentant un comportement de coefficient de poisson à gradient
US10479004B2 (en) 2014-07-25 2019-11-19 The Florida State University Research Foundation, Inc. Material systems and methods of manufacture for auxetic foams
WO2016014782A1 (fr) * 2014-07-25 2016-01-28 The Florida State University Research Foundation, Inc. Systèmes de matériaux et procédés de fabrication pour des mousses auxétiques
GB2542976A (en) * 2014-07-25 2017-04-05 Univ Florida State Res Found Material systems and methods of manufacture for auxetic foams
US11498248B2 (en) 2014-07-25 2022-11-15 The Florida State University Research Foundation, Inc. Material systems and methods of manufacture for auxetic foams
GB2542976B (en) * 2014-07-25 2020-11-11 Univ Florida State Res Found Inc Material systems and methods of manufacture for auxetic foams
CN105001622A (zh) * 2015-07-29 2015-10-28 国家纳米科学中心 一种负泊松比多功能海绵及其制备方法
WO2018213590A1 (fr) 2017-05-18 2018-11-22 Auxadyne, Llc Procédé et appareil destinés à produire une mousse auxétique
EP3625017A4 (fr) * 2017-05-18 2021-02-24 Auxadyne, LLC Procédé et appareil destinés à produire une mousse auxétique
US11148328B2 (en) 2017-05-18 2021-10-19 Auxadyne, Llc Method and apparatus to produce auxetic foam
JP2020533458A (ja) * 2017-09-13 2020-11-19 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ 三軸圧縮によるオーセチックポリウレタン及びメラミン発泡体
WO2019053143A1 (fr) * 2017-09-13 2019-03-21 Basf Se Mousses auxétiques de polyuréthane et de mélamine par compression triaxiale
US11759983B2 (en) 2017-09-13 2023-09-19 Basf Se Auxetic polyurethane and melamine foams by triaxial compression
CN112512772A (zh) * 2018-05-31 2021-03-16 耐克创新有限合伙公司 用于鞋类物品的缓冲构件及相关方法
US11529783B2 (en) 2018-05-31 2022-12-20 Nike, Inc. Cushioning member for article of footwear and related methods
US12053948B2 (en) 2018-05-31 2024-08-06 Nike, Inc. Cushioning member for article of footwear and related methods
CN109722558A (zh) * 2019-01-14 2019-05-07 南京航空航天大学 一种具有负泊松比特性的闭孔泡沫铝材料的熔体发泡制备方法
US12123470B1 (en) * 2020-07-15 2024-10-22 United States Of America As Represented By Secretary Of The Air Force Flexible multi-material structures
CN113980346A (zh) * 2021-10-29 2022-01-28 中国科学院长春应用化学研究所 一种开孔聚氨酯负泊松比泡沫材料及其制备方法

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