An unusual match: nylon & PVC can go together.With the right compatibilizer and right processing conditions, nylon can be alloyed with less thermally stable PVC PVC: see polyvinyl chloride.
in full polyvinyl chloride
Synthetic resin, an organic polymer made by treating vinyl chloride monomers with a peroxide. to yield novel engineering alloys.
Technology for producing alloys of nylon and PVC compatibilized with proprietary ethylene terpolymers was recently developed by DuPont Packaging & Industrial Polymers in Wilmington, Del. Such alloys display an attractive combination of properties that include the flame resistance and toughness of lightly plasticized PVC together with the chemical resistance of nylon. These blends also display outstanding abrasion resistance, strength, and processability.
Formulations can vary from soft and flexible elastomers to semirigid sem·i·rig·id
Partly or moderately rigid.
(of an airship) maintaining shape by means of a main supporting keel and internal gas pressure
Adj. 1. grades. Potential applications for this technology, for which licensing is now available, include wire and cable insulation and jacketing, chemical-resistant liners, membranes, and containers.
Since PVC is prone to decompose de·com·pose
v. de·com·posed, de·com·pos·ing, de·com·pos·es
1. To separate into components or basic elements.
2. To cause to rot.
1. if exposed to temperatures much above 392 F, suitable nylons for alloying are those that melt at temperatures no higher than 419 F. That category excludes nylon 66, which melts at about 500 F. Of the nylons investigated for PVC alloys, the highest-melting was nylon 6 and the lowest-melting was amorphous nylon. In between are other commercial nylons such as 12, 612, and 1212. This alloying technology has also been demonstrated with two proprietary nylons, which are similar to nylon 66 but with lower melting temperatures. One, designated PPA-160, melts at 320 F, and PPA-180 melts at 356 F.
The compatibilizing agents that are critical to this technology are DuPont's Elvaloy terpolymers of ethylene, carbon monoxide carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; , and acrylate Noun 1. acrylate - a salt or ester of propenoic acid
salt - a compound formed by replacing hydrogen in an acid by a metal (or a radical that acts like a metal) monomers. These products have been offered commercially as polymeric plasticizers plasticizers
mostly triaryl phosphates, such as tricresyl, triphenyl phosphates, which are poisonous. See also triorthocresyl phosphate. for PVC and are designed to be fully miscible miscible /mis·ci·ble/ (mis´i-b'l) able to be mixed.
Capable of being and remaining mixed in all proportions. Used of liquids. with PVC. For use in alloying PVC with nylon, these terpolymers have been functionalized [TABULAR DATA FOR TABLE 1 OMITTED] further by grafting anhydride anhydride (ănhī`drīd, –drĭd) [Gr.,=without water], chemical compound formed by removing water, H2O, from another compound; the anhydride can also react with water to form the original compound. groups onto the copolymer copolymer: see polymer. backbone. The resultant acid-functionalized polymer has the capability to react with base-functional polymers such as nylon. These further modified terpolymers are part of DuPont's Fusabond family of modifiers.
The compounding step
Experiments with a Haake laboratory batch mixer revealed that the best procedure to minimize PVC degradation was to first mix the ethylene-terpolymer modifier (programming) modifier - An operation that alters the state of an object. Modifiers often have names that begin with "set" and corresponding selector functions whose names begin with "get". with the nylon at a temperature about 50 F above the melting point of the nylon.
This facilitated the reaction between the acid-functional terpolymer ter·pol·y·mer
A polymer that consists of three distinct monomers.
[Latin ter, thrice; see trei- in Indo-European roots + polymer.] and the amine amine (əmēn`, ăm`ēn): see under amino group.
Any of a class of nitrogen-containing organic compounds derived, either in principle or in practice, from ammonia (NH3). end groups of the nylon. The presence of the low-melting terpolymer also reduced the viscosity of the blend so that the temperature could then be lowered without encountering excessive torque. After the temperature dropped to or below 392 F, the stabilized PVC powder was added and the blend mixed until homogeneous.
Scale-up to a Buss Kneader knead
tr.v. knead·ed, knead·ing, kneads
1. To mix and work into a uniform mass, as by folding, pressing, and stretching with the hands: kneading dough.
2. continuous mixer was straightforward. The nylon and terpolymer were fed into the barrel throat and reacted and homogenized ho·mog·e·nize
v. ho·mog·e·nized, ho·mog·e·niz·ing, ho·mog·e·niz·es
1. To make homogeneous.
a. To reduce to particles and disperse throughout a fluid.
b. at high temperature. The melt temperature was decreased before the next feed port, which was about halfway down the barrel. The PVC powder was added at this second feed port, and the final blending was completed without letting the melt temperature exceed 392 F for any significant period of time.
TPE TPE Thermoplastic Elastomer
TPE Terminal de Paiement Electronique (French)
TPE Total Power Exchange
TPE Twisted Pair Ethernet
TPE Tampines Expressway (Singapore)
TPE Therapeutic Plasma Exchange alloys with nylon 6
In general, alloys of nylon 6 require a relatively high level of ethylene-terpolymer modifier to avoid decomposition of the PVC. Nylon 6's melting point of 419 F requires compounding temperatures in the region where PVC is unstable.
TABLE 2 - CHEMICAL-RESISTANT PVC/NYLON 12 FORMULATION % Retention Chemical Days @ 73 F Tensile Str. Elong. ASTM Fuel C 7 60 85 Fuel C/Methanol (70/30) 7 65 127 JP-4 Jet Fuel 7 108 112 Methanol 7 80 130 20% Sodium Hydroxide 7 101 110 10% Sulfuric Acid 7 97 99 Acetone/Water (10/90) 30 87 127 Ethylene Chloride/ Water (10/90) 30 100 104 Chloroform/Water (5/95) 30 71 88 Phenol/Water (10/90) 30 53 97 Cresol/Water (10/90) 30 52 88 Days @ 140 F 10% Hydrochloric Acid 30 82 82 10% Acetic Acid 30 95 110 10% Sulfuric Acid 30 55 77 Nickel Chloride/ Water (10/90) 30 93 88 Days @ 212 F Glycol/Water (50/50) 30 89 95 Water 30 77 54 Days @ 257 F ASTM #1 Oil 7 80 34 ASTM #2 Oil 7 87 63 ASTM #3 Oil 7 69 26
After completion of the nylon-modifier reaction, the reduction in melt temperature (necessary to avoid PVC degradation) can result in extremely high melt viscosity. In order to reduce viscosity and facilitate incorporation of the PVC, the ethylene terpolymer is added at a level of about one-half of the final polymer composition. A typical blend (see Table 1, Formula A) has thermoplastic elastomer (TPE) properties and, with the addition of antimony antimony (ăn`tĭmō'nē) [Lat. antimoneum], semimetallic chemical element; symbol Sb [Lat. stibium,=a mark]; at. no. 51; at. wt. 121.75; m.p. 630.74°C;; b.p. 1,750°C;; sp. gr. (metallic form) 6. oxide, shows a UL 94V-0 flammability rating.
Tests of chemical and solvent resistance (Table 2) show good to excellent retention ([greater than]50%) of tensile strength in most environments except Fuel C. The latter contains 50% toluene toluene (tōl`yēn') or methylbenzene (mĕth'əlbĕn`zēn), C7H8 , which is an excellent solvent for PVC. The alloy is attacked by Fuel C because the PVC is plasticized by it. The PVC together with ethylene terpolymer forms the continuous phase and the nylon is the discontinuous phase in these particular blends.
Chemical-resistant grades with nylon 12
Because nylon 12 melts about 95 [degrees] F lower than nylon 6, the mixing temperature can be greatly reduced. Consequently, less ethylene-terpolymer modifier is needed to avoid PVC degradation. This allows incorporation of nylon 12 at levels approaching 50%.
The morphology of the blend, as confirmed by transmission electron microscopy “TEM” redirects here. For other uses, see TEM (disambiguation).
Transmission electron microscopy (TEM) is an imaging technique whereby a beam of electrons is transmitted through a specimen, then an image is formed, magnified and directed to appear either , shows that the nylon and PVC phases are co-continuous. This results in substantial improvements in physical properties (Table 1, Formula B). This blend also displays outstanding resistance to a wide variety of chemicals (Table 2), including simulated aqueous waste streams containing high levels of chemical contaminants. As expected, Fuel C resistance is excellent as a result of increased nylon content in the blend.
A third composition (Table 1, Formula C) was formulated as a typical electrical-jacketing grade displaying toughness, flexibility, and excellent aging resistance.
All of these blends exhibit excellent extrusion and molding processability. In addition, blend B was extrusion blow molded into cylindrical one-liter bottles (see photo on facing page). Production of these bottles was made easy by the composition's exceptional melt strength at 374 F.