Pebax Poly

PEBAX Poly(vinyl alcohol) Carbon nanotubes OSN Oil/water emulsions [65]... 

Sorption-enhanced polymer membranes are beneficial to obtain superior permeability as well as advanced selectivity especially for carbon dioxide, hydrocarbons and VOCs because condensable gas molecules are easier to be adsorbed on the polymer surface." Recent research has focused on incorporating ethylene oxide into a polymer backbone, which has unique interaction with quadruple momentum of carbon dioxide poly(ethylene oxide) (PEO), cross-linked PEO, PEO-based block copolymers such as poly(ethylene oxide-Z)-amide) (Pebax), poly(ethylene oxide- -butylene terephthalate) (PEO-6-PBT)." ... 

Block copolymers can contain crystalline or amorphous hard blocks. Examples of crystalline block copolymers are polyurethanes (e.g. B.F. Goodrich s Estane line), polyether esters (e.g. Dupont s Hytrel polymers), polyether amides (e.g. Atofina s Pebax grades). Polyurethanes have enjoyed limited utility due to their relatively low thermal stability use temperatures must be kept below 275°F, due to the reversibility of the urethane linkage. Recently, polyurethanes with stability at 350°F for nearly 100 h have been claimed [2]. Poly ether esters and polyether amides have been explored for PSA applications where their heat and plasticizer resistance is a benefit [3]. However, the high price of these materials and their multiblock architecture have limited their use. All of these crystalline block copolymers consist of multiblocks with relatively short, amorphous, polyether or polyester mid-blocks. Consequently they can not be diluted as extensively with tackifiers and diluents as styrenic triblock copolymers. Thereby it is more difficult to obtain strong, yet soft adhesives — the primary goals of adding rubber to hot melts. 

Poly(amide-b-ethylene oxide) copolymers were presented in 1990 as a promising membrane material [43]. These block copolymers were developed in 1972 but in 1981 began to be used for commercial purpose under the trade name Pebax , produced by ATOCHEM [44] (now ARKEMA). Another important group of segmented poly(ester)s used for membranes are block copolymers based on PEO and PBT (poly(butylene tereph-thalate), known under commercial name of Polyactive [45]. By changing the polyamide and polyether segment, molecnlar mass and the content of each block, the mechanical, chemical, and physical properties are nicely tnned as well [46]. 

Figure 12.1 presents the chemical structure of poly(amide-b-ethylene oxide) (commercial name Pebax ) and poly(ethylene oxide)-poly(butylene terephthalate) (PEO-PBT) (commercially known as Polyactive ). These copolymers with high content of PEO are hydrophilic and show excellent chemical resistance towards solvents. The solubility of these copolymers in different solvents is determined by the ratio of segmented blocks. Pebax MH 1657 is soluble only in few solvents and generally the polymer solution is prepared under reflux at high temperature and low polymer concentration by using n-butanol or a mixture of n-butanol/l-propanol, after cooling down to room temperature. 

It should be noted that Car et al. [10,11] (see also Chapter 12 of this volume) worked independently on similar blend manbranes, which were made of Pebax 1657, a grade of commercial poly(amide-b-ether) block copolymer with six polyamide blocks, and free PEG. Those membranes were also shown to exhibit high selectivity and permeability performances, which were attribnted to changes in both the chemical composition (i.e. higher EO content) and the morphological stmctuie (i.e. lower material crystallinity). On the contrary, Jaipurkar [12] observed CO2 permeability and selectivity improvements for the blend of Pebax 2533 with 25% of PEG 10000, bnt not for the blends with other PEG molecular weights or composition. 

The poly(ether amides) (commercial PEBAX by Elf Atochem) are listed in Table 1. 

Table 1. PEBAX grades and their designation. Soft block weight fraction indicated by the first two digits. Soft and hard block polymers PTMO - poly(tetramethylene oxide) PEO - poly(ethylene oxide) PA6 - polyamide-6 PA12 - polyamide-12...

Sheth J P, Xu J and Wilkes G L (2003) Solid state structure-property behavior of semicrystaUine poly(ether-61ocfc-amide) PEBAX thermoplastic elastomers. Polymer 44 743-756. 

Detailed information on the synthesis of PEBA is presented in Chapters 2 and 10 and also in [13-16]. However, it is worth mentioning here that commercially available poly (ether- -amide) PEBAX copolymers are synthesized by melt polycondensation of carboxylic acid-terminated amide blocks with poly-(oxyalkylene glycol)s. The polymerization is catalyzed by a metal alkoxide Ti(OR)4 and is carried out at elevated temperatures of ca. 230°C under vacuum. These copolymers are marketed for use in many areas, a few of which include sports equipment, automotive components, applications that require polymers with antistatic properties, and also in biomedical applications, such as tubing and catheter balloons [17]. There is also a growing body of literature on the use of PEBAX in the manufacture of membranes for gas separations. Vestamid E-Series elastomers marketed by Degussa-Htils are another commercial example of PTMO-PA12 based PEBA copolymers. 

Since the introduction of PEBAX by Atochem, many research groups have devoted much effort in the study of the morphology and properties of these copolymers, in addition to other PEBA systems consisting of various polyamides, such as nylon 6, nylon 11, nylon 12, etc., and polyesters, such as PTMO, poly (ethylene oxide) (PEO), and poly(propylene oxide) (PPO). This chapter aims to present an overview of these materials its scope is limited to the solid-state structure-property relationships and uniaxial deformation behavior of the PEBA copolymers. It is divided into two main sections. PTMO-PA12 systems are first presented and, in the second section, systems based on PEO or PTMO... 

Figure 4.7 Structure of poly(amide- -ethylene oxide) (PEBAX).

Interesting advances in the field of GS membrane materials are polymers with high-free volumes, such as poly(l-trimethylsilyl-l-propyne), poly(4-methyl-2-pentyne), and polymers of intrinsic microporosity [108]. Regarding the emerging application of CO2 capture, the copolymer class Pebax (Arkema) showed promising results. For instance, Bondar et al. [109] reported interesting values of CO2/N2 and CO2/H2 selectivity for different grades of Pebax membranes. 

However, the crystallinity of the native polymer is not usually subject to variation in nanocomposite films. For example, it has been shown that the addition of CaCOs or Si02 into polypropylene (PP), or of nano-sized mont-morillonite clays into polyamide PA6-matrices or Ti02 into poly(ethylene oxide-fi-amide-6) (PEBAX), does not affect the content of crystallinity of the polymer (Zoppi et al, 2000 Rong et al, 2001 Varlot et al, 2002 Sheng et al, 2004). 

Braided Composite Tube in Catheter. The composite tubes, as shown in Figure 1, have nominal inner and outer diameters of 0.116 (2.95 mm) and 0.165 (4.19 nun), respectively. The polymer layers were extmded from the same TPE compound, namely poly(ether-block-amide) copolymer, Pebax 7233 resin filled with 30 % (w/w) BaS04 radiopaque powders. The 16 strands of the 0.001 by 0.005 fiat wires of stainless steel 304V were braided onto the inner polymer layer with the one-over-one pattern at the plaiting rate of 28 picks per inch (PPI). After braiding, the extruded outer polymer layer was manually applied onto the inner, braided polymer layer. 

The fiber used in this study was Twaron 2200 a poly(p-phenylene terephthalamide) (PPTA) aramid fiber, supplied by Akzo Nobel Research (Arnhem). The fibers have modulus Ef= 136 GPa, tensile strength, thermoplastic elastomer, polyether amide block copolymer supplied by Atofma known commercially as Pebax . These thermoplastic elastomers (TPE) consist of linear chains of hard polyamide (PA) blocks covalently linked to soft polyether (PE) blocks via ester groups. The grade of Pebax used was Pebax 7033, with a modulus Eva. = 128 MPa, yield stress ay = 32 MPa, Yield strain ey = 25 %, ultimate failiue stress a m = 67 MPa and an ultimate strain e m = 400 %. 

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