JP2604347B2 - Coated extended chain polyethylene fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Fibers of polyethylene (extended chain: sometimes abbreviated as EC in the following) and polypropylene of extended chain having extremely high strength and tensile modulus are known. The material is Pennings
It is disclosed in various publications by Professor and his co-workers Smith and Lemstra, and in co-pending patent applications (Kavesh et al). These mechanical properties are imparted to fibers by a process that involves drawing ultra-high molecular weight polyolefin from a supersaturated solution or spinning a hot solution of ultra-high molecular weight polyolefin from a die to form gel fibers. At least partially due to the high degree of crystallinity and orientation achieved. Subsequent processing, especially the stretching step, gives the polyolefin a high degree of crystallinity and orientation.

Unfortunately, such extended chain polyolefin fibers have two disadvantageous properties that directly result from high crystallinity and orientation. First, the longitudinal orientation causes the fiber to have a very low transverse strength, so that when the fiber is subjected to friction or self-friction, especially when twisted or processed into fabric, fibrils Tends to This fibrillation is an undesirable feature in many applications, such as ropes, sutures or fabrics. A second disadvantageous property of extended chain polyolefin fibers is that, due to their crystallinity, the adhesion of the fibers to most matrix materials is low. This tends to limit the usefulness of these fibers in composite structures.

Coating extended chain polyethylene fibers with polyethylene or ethylene copolymer materials reduces the tendency of the fibers to fibrillate and increases their lateral strength, allowing the fibers to be used alone or in composite structures with various matrix materials. And these results were achieved without significant loss of strength and tensile modulus for the fiber alone, and in some cases could be attributed to an annealing effect on fiber defects. However, it has been found that it may even improve the above properties. The coated fiber can be used alone under appropriate temperature and pressure conditions to produce a simple composite.

Therefore, the present invention has a weight average molecular weight of at least
At least one of the constituent filaments of the undrawn polyethylene gel spun multifilament fiber produced by spinning 500,000 polyethylene from the solution to form gel fibers, extracting the solvent from the formed gel fibers, and drying. A strength of at least 15 g / denier, obtained by coating on one part a polymer having a crystallinity of at least 10% by volume of ethylene in an amount of from 0.1 to 200% by weight and then stretching under heating;
A fiber having an average tensile modulus of at least 300 g / denier, having improved strength and tensile elastic properties as compared to the same uncoated fiber, and having reduced fibrillability; Molecular weight of at least 50
It relates to a coated polyethylene fiber which is 0,000.

The coated fibers of the present invention (which form part of the composite structure of the present invention) are ultra-high molecular weight extended chain polyethylene. Suitable polyethylene fibers have at least about 500,00
It is made from polyethylene having a weight average molecular weight of 0, preferably at least about 1 × 10 ⁶ , more preferably about 2 to about 5 × 10 ⁶ . The fibers can be obtained by the solution method detailed in U.S. Pat. No. 4,356,138, filed Jan. 15, 1981 (U.S. Pat. No. 225,288), or by various publications of Pennings et al. And U.S. Pat. No. 4,187,394 ( Meihuisen, etc.)
Polyolefins can be made by other solution methods, including stretching from supersaturated solutions, including those described in US Pat. The polyethylene fibers are prepared by spinning a polyethylene solution and cooling to form a gel structure, particularly as disclosed in U.S. Patent No. 4,413,110 filed April 30, 1981 (U.S. Patent Application No. 259,266 (Kavesh et al.)). And other methods of solution spinning (gel) such as those described by Pennings and co-workers in various other research articles, such as Smith and Remstra. Publications and patent applications, such as those described in GB 2,051,667 and DE-A 300 46 99, or similar techniques, which can be formed by melt spinning under controlled conditions. Polyethylene fibers, for example, US Pat.
No. 8,118 or British Patent 1,469,526 can likewise be used, but are generally less suitable than fibers produced by drawing from a supersaturated solution or by spinning and gelling the solution.

The polyethylene fibers used have a tenacity value of at least about 15 g / denier, preferably at least about 20 g / denier, more preferably about 25 or 30 g / denier, most preferably at least about 40 g / denier. Accordingly, the preferred tensile modulus value for polyethylene fibers is at least about 30.
0 g / denier, preferably at least about 500 g / denier,
More preferably at least about 750 or 1,000 g / denier, most preferably at least about 1,500 g / denier. In general, the values of strength and tensile modulus are directly related and rise together relatively linearly for most of the methods used, but for some applications they have a particularly high strength or a strong strength independent of tensile modulus. Independently, it is possible to use selected fibers which have a particularly high tensile modulus, for example fibers produced by melt spinning. Thus, for example, in applications of coated fibers to sutures, the value of elongation is particularly important. For coated fibers and composites used in ballistic applications, i.e., in high shear resistance applications, both strength and tensile modulus values are very important.

Although the melting point of polyethylene fiber is not particularly critical in the present invention, the melting point of polyethylene fiber is generally about 138 ° C or higher (for example, 145 to 155 ° C). Other properties are not critical, but may be important for certain applications, such as work-to-break (measured according to ANSI / ASTM D-2256), creep (e.g.,
% Under 50% load), elongation at break, elongation at yield,
Includes UV stability, oxidation stability, heat stability and hydrolysis stability. Most, if not all, of these properties obtained with polyethylene fibers will correspond to similar linear dependence or increased values for the coated polyethylene fibers.

The polyethylene fiber used in the present invention is a multifilament. Multifilaments of 2 to 500 or more strands are contemplated, and arrangements can be perfectly parallel filaments, stranded, filament, braided and stranded strands.
In the case of multifilaments other than the parallel arrangement,
Before, during or after the application of the coating, the winding or other arrangement of the filaments can take place. Further, the coated fibers of the present invention can be very long fibers (sometimes referred to as being of virtually infinite length), relatively short pieces, or very short pieces, such as resins (eg, bulk molding compounds or sheet moldings). (Compound) reinforcing fiber.

Suitable coating materials for the coated fibers of the present invention are various forms of polyethylene and various forms of ethylene polymers having at least 10% ethylene crystallinity. Polyethylene coatings have low density (for example,
(Specific gravity of about 0.90 to 0.94) or high density (for example, specific gravity of about 0.
94-0.98) and is generally "polyethylene"
Various amounts of branching, linearity, relatively small amounts of comonomer, molecular weight,
It has values such as melt viscosity. High density polyethylene is preferred for some applications, while low density polyethylene is preferred for other applications.

Suitable ethylene copolymer coatings are copolymers of ethylene with one or more other olefinically unsaturated monomers, said monomers being selected from several broad classes. Some broad classes of comonomers are 1-monoolefins and olefins having one polymerizable terminal double bond and one or more internal double bonds.

In many applications, the ethylene content of the copolymer is about
Greater than the minimum required to achieve 10% by volume ethylene crystallinity. In particular, to increase the adhesion of the coating to the fibers, the crystallinity of ethylene is preferably at least about 25% by volume, more preferably about 50% by volume, and most preferably at least about 70% by volume. These values can be found, for example, in the Encyclopedia of Polymer Techno
logy, page 355, 3, 9 and 18 branches / 100, corresponding to 90%, 80% and 70% ethylene crystallinity
Achieved in ethylene butene-1 copolymers shown as 0 carbon atoms. 5, 10 and 15 mol% ethylene acetate vinyl acetate copolymers are almost
This corresponds to a crystallinity of 55%, 40% and 25%.

However, the coating materials of the present invention, including the above-mentioned coating materials, do not include natural and synthetic waxes.

The ratio of coating to fiber can vary over a wide range depending on the application using the coated fiber. A typical wide range is from about 0.1 to about 2 for fibers
It is a coating of 00% by weight. For coated fibers to be used in purely fiber applications, such as in ropes, sutures, etc., the preferred amount of coating is about 10% of the fiber.
About 50% by weight. When using coated fibers to form a simple composite in which the coating melts into a continuous matrix, the same or lower ratios can be used. For other applications, such as composites containing other fibers (eg, glass fibers) and / or fillers, higher amounts of coating may be preferred, where the amount of coating is preferably
50-200%, more preferably 75-150%, most preferably
75-100%.

The coating can be applied to the fiber in various ways. One method is to apply the pure resin coating material to liquids, suspended sticky solids or particles, or high tensile modulus fibers drawn as a fluidized bed. Alternatively, the coating can be applied as a solution or emulsion in a suitable solvent that does not adversely affect the properties of the fiber at the application temperature. While any of the solvents that can dissolve or disperse the polymer of the coating can be used, a preferred group of solvents includes paraffin oils, aromatic or hydrocarbon solvents, examples of particular solvents are paraffin oil, xylene, toluene and octane. is there. The techniques used to dissolve or degrade the coating polymer in the solvent are those commonly used for coating similar polymeric materials on various supports.

Other techniques for applying a coating to the fiber, such as coating a precursor with a high tensile modulus, before or after removing the solvent from the fiber, before the drawing operation is performed at an elevated temperature, can be used. The fiber can then be drawn at an elevated temperature to produce a coated fiber. The extruded gel fibers can be passed through a solution of a suitable coating polymer (the solvent can be a paraffin oil, an aromatic solvent or an aliphatic solvent) under conditions to achieve the desired coating. Crystallization of the high molecular weight polyethylene in the gel fibers may or may not occur before the fibers enter the cold solution. Alternatively, the fibers can be extruded into a fluidized bed of a suitable polymer powder.

In addition to the coating of the polymer, fillers such as carbon black, calcium carbonate, silica or barium ferrite can be added to obtain the desired properties. For example, carbon black can be added to achieve UV protection and / or increased conductivity.

Further, if the polyethylene fiber acquires its final properties only after the drawing operation or after other processing methods, such as solvent exchange, drying, etc., the coating can be applied to the precursor material of the final fiber. In such a case, the desired and preferred strength, tensile modulus and other properties of the fiber should be determined by continuing the treatment on the fiber precursor in a manner corresponding to the coated fiber precursor. is there. Thus, for example, a coating may be applied to the xerogel fibers described in U.S. Pat. No. 4,413,110 and its co-pending application (Kavesh et al.), And the coated xerogel fibers then subjected to conditions of defined temperature and draw ratio When drawn, the fiber tenacity and the tensile modulus of the fiber are measured on similarly drawn uncoated xerogel fibers.

The coated fibers of the present invention can be further processed for use in a variety of applications, such as making composites, wovens, felts, fabrics, nonwovens and knitted articles using the coated fibers alone.

Further, the coated fibers of the present invention can be used to form complex composite structures. Such complex composites contain the aforementioned coated fibers. Here, the coated fibers may be of the usual type of network, such as perfectly parallel fibers, layers of parallel fibers that are rotated between layers in various ways, fibers of irregular orientation and of various lengths. (Including felt) and other arrangements. In addition to such a network of coated fibers, complex composites include a different matrix than the coating material. The matrix can be a thermoset, thermoplastic, elastic, or various non-polymeric materials. Examples of suitable matrix materials include thermosetting polymers such as epoxies, unsaturated polyesters, polyurethanes, multifunctional allyl polymers (eg, diallyl phthalate),
Urea-formaldehyde polymers, phenol-formaldehyde polymers and vinylester resins; thermoplastic matrices such as poly-1-butene, polystyrene, styrene copolymers, polyvinyl chloride and ABS
Resins; elastomeric matrices such as polybutadiene, butadiene copolymers, thermoplastic elastomers (eg, polystyrene-polyisoprene-polystyrene, polystyrene-polybutadiene-polystyrene and polystyrene-halogenated diene-polystyrene), sulfonated ethylene-propylene diene terpolymers and the like. Metal salts of terpolymers as well as non-polymeric substrates such as concrete. Such composite structures have particular utility in ballistic applications, boat hulls, motorcycle helmets, road surface layers, architectural structures, films, hoses and belts. Composite structures can be used to cut the coated fiber shreds of the present invention alone (simple composites) or together with other thermoplastics and thermoset matrices (so-called complex composites and are described in more detail herein). Structure).

In addition to coated fibers and matrices, other materials, such as lubricants, fillers, adhesives, other fiber materials (eg, aramid, boron fibers, glass fibers, glass microballoons, graphite fibers and mineral fibers, such as mica, water (Lastonite and asbestos) can be present in complex composites in various regular or irregular geometries. For composite structures where strong adhesion between the coated polyethylene fibers and the matrix is desired, the coating is selected to provide good adhesion to the matrix material. In general, adhesion can be improved by using as a coating material an ethylene copolymer having comonomers with properties, properties similar to the ionic, aromatic or other properties of the matrix. For example, in the case of an epoxy-based matrix, a relatively ionic comonomer, such as acrylic acid, vinyl acetate or methacrylic acid, generally results in a coating on the epoxy-based matrix as compared to the adhesion of the corresponding uncoated fiber to the same epoxy-based matrix. Will improve fiber adhesion. For polyester-based matrices, some preferred comonomers in the coating are acrylic acid, 1,4-hexadiene, vinyl alcohol, and free radically polymerizable monomers (eg, acrylates). Also suitable are block and graft copolymers of polyethylene and polybutadiene, and reaction products of ethylene-acrylic acid copolymers with glycidol methacrylate. In the case of a matrix composed of polyurethane, an example of a preferred coating is a hydroxyl-containing polyethylene copolymer, for example an ethylene-vinyl alcohol copolymer. Corresponding representative preferred comonomers of various suitable thermoplastic matrices and coating materials are shown in Table 1 below.

The properties of these complex composites generally include a variety of advantageous properties derived from the coated fibers, including, especially for the extended chain polyethylene fiber component of the coated fibers, special strength and tensile moduli, In some cases, it also includes dimensional stability, low water absorption and chemical stability. Complex composites can also have advantageous properties derived from the matrix material, such as high heat distortion temperatures, appropriate flexibility or stiffness and abrasion resistance. The coating component may, as described above in connection with the novel coated fiber, improve the mechanical properties of the composite, except for improving the inherent properties of the extended chain polyethylene, for example, by improving the transverse strength of the multifilament fiber. Or to other properties generally do not contribute substantially.

Further, the proportion of coated fibers (or extended chain polyethylene fibers) in the composite is not critical and can have preferred values for various applications.

The coated fibers and complex composite structures of the present invention can be formed into various articles. For example, vests containing knitted or woven or nonwoven fabrics of the coated fibers of the present invention, relatively rigid portions of the composites of the present invention, or combinations thereof, can be made. Helmets can be made with the complex composites of the present invention using a thermoset matrix. If ballistic resistant articles are required, shields for helicopters, tanks, and other articles can also be formed from the coated fibers or complex composites of the present invention, where the matrix material is particularly desirable for the shielding material Selected based on physical properties.

In other applications, the complex composites of the present invention can be formed into various common geometries.

The coating of the polyethylene / ethylene copolymer can be crosslinked by known mechanical techniques, for example using a peroxide, sulfur or radiation curing system, or by reacting with a multifunctional acid chloride or isocyanate. A cross-linked coating can be obtained on fibers of tensile modulus.

REFERENCE EXAMPLE A Ultra high molecular weight polyethylene (intrinsic viscosity, 17 dl / g in decalin at 130 ° C.) was dissolved in paraffin oil as a 7% by weight solution at 220 ° C. This solution was extruded through a die having 16 holes (hole diameter 1 mm) to produce a gel fiber at a speed of 1.8 m / min. The fiber was extracted with trichlorofluoroethane and dried. The filament is stretched in a 1 m length tube at 145 ° C. and a supply roll speed of 25 cm / min at a stretch ratio of 19: 1 to give a strong 19 g / denier and a tensile modulus of 782 g /
A 625 denier extended chain polyethylene (ECPE) filament yarn having a denier and elongation at break of 44% was produced. This fiber was used in Reference Example 2.

B. Similar multifilament fibers were made at 220 ° C. using 18 IV polyethylene dissolved at 6% by weight in paraffin oil. That is, this solution was added to 16 holes (pore diameter).
Gel fibers were produced at 3.08 m / min through a 0.76 mm) die. The wet gel fibers were drawn at 100 ° C. at a draw ratio of 11: 1, extracted and dried. The 198 denier yarn produced had a tenacity of 25 g / denier, a tensile modulus of 971 g / denier and an elongation of 4.5% and was used in Reference Example 3.

Example 1 Preparation of Gel Fiber A high molecular weight linear polyethylene (intrinsic viscosity: 17.5 in decalin at 135 ° C) was dissolved at 220 ° C in paraffin oil to form a 6 wt% solution. The solution was extruded at a rate of 3.2 m / min from a die with 16 holes (hole diameter 1 mm). The oil was extracted from the fiber with trichlorotrifluoroethane, and the fiber was then dried.

Gel Fiber Coating Multifilament 35 g of low density polyethylene in 500 ml of toluene (Union Carhide DPDA 6169WT; Density
0.98; MI ₂ = 6) was passed through at a temperature of 75 ° C. and a speed of 1.5 m / min, then twice through a bath of trichlorotrifluoroethane and finally dried. The fiber gained 19.5% in weight.

Stretching of the Fiber The coated fiber was stretched in a 100 cm length tube heated to 140 ° C. at a feed roll speed of 25 cm / min at a draw ratio of 20: 1 to produce a 208 denier filament. Tensile tests on the coated fibers showed a tensile strength of 19.9 g / denier and a tensile modulus of 728 g / denier.

The uncoated fiber was drawn in the same manner to produce a multifilament yarn. The tensile test of this uncoated fiber is 18.9
g / denier tensile strength (tensile) and 637 g / denier tensile modulus.

As can be seen from the data, the coated fiber is
Despite the fact that 20% of the fiber weight consists of a coating of low density polyethylene, it has a higher tensile strength and modulus.

In contrast, the law of mixing (ignoring secondary effects) is that the tensile modulus of the coated fiber will be 0.8 × 638 = 509 g / denier and the tensile strength of the coated fiber will be 0.8 × 18.
9 = 15.1 g / denier.
Actual values are 143% and 132% of theory.

The coated fibers were then tied around small pillars to make five knots (each knot was tied under the previous knot). Examination by light microscopy showed that no fibrillation occurred. This is a particularly significant result for suture applications.

REFERENCE EXAMPLE 2 13 denier ECPE filament from A in Reference Example 1 (tensile modulus 732 g / denier, tensile strength 19 g / tener) was mixed with ethylene-acrylic acid copolymer (Dow EAA-455, 0.932 per g polymer) in toluene. (Containing milliequivalents of acrylic acid) under the conditions shown in Table 2. The fibers were removed, air dried and subsequently embedded in epoxy resin (Devkon5 Epoxy, Devcon Corporation) to a depth of 5 mm. At room temperature
Cured for hours and then heated in an air circulating oven to 100 ° C. for 30 minutes.

The fiber was pulled at 1 inch / minute (2.54 cm / minute) on an Instron tensile tester. As the results in Table 2 (average of two experiments) show, under all conditions of immersion evaluated, the adhesion was improved over the unmodified fiber. Under the best conditions (one experiment for sample C), the fibers broke without being pulled out of the resin.

Reference Example 3 The strength of 25 g / denier from B in Reference Example 1 and
Extended chain polyethylene fibers with a tensile modulus of 971 g / denier contain various polymers in xylene solution (60 or
(Concentration of 120 g / 1) Coating in one of two treatment modes. First
Was to soak the fibers in the solution for 2 minutes and then dry. The second mode was to soak for 30 seconds, air dry for 3 minutes, then soak for 2 seconds (to repeat 4 times), and then dry for 3 minutes. Then, all of the coated fibers were placed in a rectangular parallelepiped mold of epoxy resin (the same resin as in Reference Example 2), and then this was heated at 25 °
Cured for 24 hours.

A force is then applied to the end of the fiber to provide 2 inches / minute (5.1 cm /
Minute) and pulled out of the cured epoxy resin. To measure the force ( "Fpo") when pulling was calculated at break shear stress ( "S _B"). Table 3 shows the results.

* The polymers used were as follows.

EAAO- low molecular weight acid number 120 ethylene - acrylic acid copolymers are commercially available from Allied Corporation as AC ^R -5,120 copolymer.

PE-AA-a polyethylene-grafted acrylic acid with 6% acrylic acid, sold by Leicophord Chemical as PE-452.

EAA2 mono-acid number 49.2 ethylene-acrylic acid copolymer, Do
Sold by Dow Chemical as w-PE-452.

EAA5-Ethylene-acrylic acid copolymer with an acid value of 52, EAA
Sold by Dow Chemical as -455.

OPE2- oxidized polyethylene having an acid value of 28, available from Allied Corporation as AC ^R over 392 polyethylene oxide.

OPE6- acid value 16 oxidized polyethylene, sold by Allied Corporation as AC ^R 316A oxidized polyethylene.

Example 2 Continuous Coating of Polyethylene Fibers with Ethylene Acrylic Acid Copolymer Preparation of Gel Fibers Ultra High Molecular Weight Polyethylene (Decalin 7.5 at 135 ° C.)
(dl / g intrinsic viscosity) was dissolved in paraffin oil at 220 ° C. as a 6% by weight solution. This solution was extruded through a die having 16 holes (hole diameter 1.0 mm) to produce gel fibers at a speed of 8.2 m / min. The fiber was extracted with trichlorotrifluoroethane and dried.

Fiber Coating Dried undrawn fiber (7.0 g) was mixed with 24 g of dissolved ethylene acrylic acid copolymer (Dow EAA-455 copolymer, acid number = 52.3, ie, 5 g to neutralize 1 g of sample).
(Requires 2.8 mg of calcium hydroxide) in 600 ml of toluene at 105 ° C. at a speed of 1.5 m / min. After passing through this solution, the fibers were passed through trichlorotrifluoroethane and then dried to give a fiber weight of 8.06 g. The fiber is then placed in a 100 ° C. tube at 140 ° C.
The film was stretched at a supply roll speed of 25 cm / min. The resulting fiber is 2
It had 34 denier, 20.2 g / denier strength, 696 g / denier tensile modulus and 3.9% ultimate elongation.

Adhesion to epoxy resin Adhesion to epoxy resin was measured in the same manner as in Reference Example 3. The force required to withdraw from the matrix was 1.33 N (0.30 lb) and the shear stress was 2340 kPa (340 lb / in).

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Cieldon Cabecciyu, New Jersey, United States of America 07981 Whitspany-Nose Pond Road 16 (72) Inventor Igor Paris-New Jersey, United States of America -Georgia 07940 Madison Dane Street 18 (72) Inventor: Dassan Cyril Prevossek, New Jersey, United States 07960 Morristown Harwich Road 21 (56 References JP-A-55-107506 (JP, A) JP-A-49-75819 (JP, A) JP-B-41-11679 (JP, B1) JP-B-43-27538 (JP, B1) 38-10359 (JP, B1) West German application publication 1097403 (DE, B2)

Claims (12)

(57) [Claims] Claims: 1. A polyethylene having a weight average molecular weight of at least 500,000 is spun from a solution thereof to form a gel fiber;
Having at least 10% by volume of ethylene crystallinity on at least a portion of the constituent filaments of the undrawn polyethylene gel spun multifilament fiber produced by extracting the solvent from the formed gel fiber and drying. Having a coating obtained by coating the polymer in an amount of 0.1-200% by weight and then stretching under heat, having a strength of at least 15 g / denier and a tensile modulus of at least 300 g / denier A coated polyethylene fiber having a weight average molecular weight of the fiber of at least 500,000, having improved strength and tensile elastic properties as compared to the same fiber and having reduced fibrillability. 2. The method according to claim 1, wherein said polyethylene fiber is at least 1,000,
2. The coated polyethylene fiber of claim 1 having a weight average molecular weight of 000. 3. The method of claim 2, wherein said coating is polyethylene.
3. A coated polyethylene fiber according to claim 1 or claim 2. 4. A coated polyethylene fiber according to claim 1, wherein said coating is a copolymer of ethylene having a crystallinity of ethylene of at least 10% by volume. 5. The method of claim 1, wherein said copolymer of ethylene is at least 25.
5. The coated polyethylene fiber of claim 4 having a volume percent ethylene crystallinity. 6. A composite comprising a network of coated polyethylene fibers and a matrix, said coated polyethylene fibers comprising spinning a polyethylene having a weight average molecular weight of at least 500,000 from a solution thereof to form gel fibers. Crystallization of at least 10% by volume of ethylene on at least a portion of the constituent filaments of an undrawn polyethylene gel spun multifilament fiber produced by forming, extracting a solvent from the formed gel fiber and drying. A polymer having a strength of at least 15 g / denier and a tensile modulus of at least 300 g / denier, obtained by coating the polymer having a degree of 0.1 to 200% by weight and then stretching under heating; Has improved strength and tensile elastic properties compared to the same fiber without the coating, One fibrillation resistance deteriorated, polyethylene fiber weight average molecular weight of fibers coated at least 500,000, said complex. 7. The method according to claim 1, wherein said polyethylene fiber is at least 1,000,
7. The conjugate according to claim 6, having a weight average molecular weight of 000. 8. The coating according to claim 1, wherein said coating is polyethylene.
A composite according to claim 6 or claim 7. 9. A composite according to claim 6, wherein said coating is a copolymer of ethylene having an ethylene crystallinity of at least 10% by volume. 10. The method of claim 10 wherein said ethylene copolymer is at least 25.
10. The composite of claim 9, having a volume percent ethylene crystallinity. 11. The composite according to claim 6, wherein said matrix is a thermosetting polymer. 12. The composite according to claim 6, wherein said matrix is an epoxy matrix.