Terpolymers, structural

However, more recently, the ethylene-vinyl acetate-carbon monoxide (E-VA-CO) terpolymers (Tg = —32 °C), offering a more complete miscibility with PVC, because of the polar keto groups in the terpolymer structure, have replaced the EVA copolymers for fiexibilizing the PVC. The E-VA-CO/PVC blends exhibit a single Tg behavior, indicating the complete miscibility (McConnell et al. 2004). Thus, the E-VA-CO terpolymer is more effective as a miscible, polymeric plasticizer for effectively lowering the Tg of PVC to make it more fiexible. 

Fig. 3. Generalized terpolymer structure for vinyl acetal polymers, R = C3H7 for poly(vinyl butyral) PVB and R = H for poly(vinyl formal) PVF. Ranges for commercial grades of Butvar PVB from Solutia and Pioloform B PVB from Wacker include the following X, vinyl butyral, is 52-74 mol% or 77-90 wt% y, vinyl alcohol, is 26-45 mol% or 10-20 wt% z, vinyl acetate, is 0-4 mol% or 0-3 wt% (19,20). For commercial grades of Vinylec PVF from Chisso x, vinyl formal, is 73-79 mol% or 80-86 wt% y, vinyl alcohol, is 10-14 mol% or 5.0-6.5 wt% z, vinyl acetate, is 10-14 mol% or 9.5-13 wt% (21)...

The influence of the terpolymer structure on solubility and compatibility can be generally described by Fig. 8. ... 

A periodic A2B-type copolymer (2 1 monomer composition) having an ABC-type periodic terpolymer structure was produced from OZO and glutaric anhydride (Scheme 28). From OZO, a unit structure of reaction 6 (Scheme 1) is formed. 

AEM terpolymers contain an organic acid cure site monomer and are usually vulcanized with primary diamines. The terpolymer structure and vulcanization mechanism are shown schematically in Figure 6.3. 

In attempts to further improve the stability of fluorine-containing elastomers Du Pont developed a polymer with no C—H groups. This material is a terpolymer of tetrafluoroethylene, perfluoro(methyl vinyl ether) and, in small amounts, a cure site monomer of undisclosed composition. Marketed as Kalrez in 1975 the polymer withstands air oxidation up to 290-315°C and has an extremely low volume swell in a wide range of solvents, properties unmatched by any other commercial fluoroelastomer. This rubber is, however, very expensive, about 20 times the cost of the FKM rubbers and quoted at 1500/kg in 1990, and production is only of the order of 1 t.p.a. In 1992 Du Pont offered a material costing about 75% as much as Kalrez and marketed as Zalak. Structurally, it differs mainly from Kalrez in the choice of cure-site monomer. 

In 1991 MMM announced Fluorel II, a terpolymer of tetrafluoroethylene, vinylidene fluoride and propylene. As might be expected from the structure, this is intermediate between FKM and Aflas, having better resistance to many newer automotive oils, lubricants and transmission fluids than the former but better heat resistance than the latter. 

A VDF unit also follows FIFP m the structurally much more complex terpo-lymers [30] Dipolymers contain 60 wt % VDF (66% F) and terpolymers contain 33-50 wt % VDF (66-69 5% F) and generally less than 28 wt % TFE Molecular weights range from 1 5 x 10 to 10 Their respective continuous service temperature ranges are -18 to 210 °C and -12 to 230 °C Dipolymer vulcanizates retam over 50% of their tensile strength for more than 1 year at 200 °C or for 2 months at 260 C... 

Composite proplnts, which are used almost entirely in rocket propulsion, normally contain a solid phase oxidizer combined with a polymeric fuel binder with a -CH2—CH2— structure. Practically speaking AP is the only oxidizer which has achieved high volume production, although ammonium nitrate (AN) has limited special uses such as in gas generators. Other oxidizers which have been studied more or less as curiosities include hydrazinium nitrate, nitronium perchlorate, lithium perchlorate, lithium nitrate, potassium perchlorate and others. Among binders, the most used are polyurethanes, polybutadiene/acrylonitrile/acrylic acid terpolymers and hydroxy-terminated polybutadienes... 

Structural Factors and Tensile Properties of Ethylene-Propylene—Diene Terpolymers Prepared with Various Catalyst Systems... 

Ethylene-propylene-diene terpolymers (EPDM), with their inherent complexity in structural parameters, owe their tensile properties to specific structures dictated by polymerization conditions, among which the controlling factor is the catalyst used in preparing the polymers. However, no detailed studies on correlation between tensile properties and EPDM structures have been published (l,2). An unusual vulcanization behavior of EPDMs prepared with vanadium carboxylates (typified by Vr g, carboxylate of mixed acids of Ccj-Cq) has been recently reported Q). This EPDM attains target tensile properties in 18 and 12 minutes at vulcanization temperatures of 150 and l60°C respectively, while for EPDMs prepared with V0Cl -Et3Al2Cl or V(acac) -Et2AlCl, about 50 and 0 minutes are usually required at the respective vulcanization temperatures, all with dieyclopentadiene (DCPD) as the third monomer and with the same vulcanization recipe. This observation prompted us to inquire into the inherent structural factors... 

Multiblock copolymeric structures containing PCHD blocks were also synthesized using s-BuLi as the initiator and either TMEDA or DABCO as the additive. Sequential monomer addition was performed with CHD being the last monomer added in all cases [35]. The structures prepared are PS-b-PCHD, PI-fc-PCHD and PBd-b-PCHD block copolymers, PS-fo-PBd-fo-PCHD, PBd-fr-PS-b-PCHD and PBd-fo-PI-fr-PCHD triblock terpolymers, and PS-fc-... 

Anionic polymerization techniques were also critical for the synthesis of a model cyclic triblock terpolymer [cyclic(S-fo-I-fr-MMA)] [196]. The linear cctw-amino acid precursor S-fr-I-fr-MMA was synthesized by the sequential anionic polymerization of St, I and MMA with 2,2,5,5-tetramethyl-l-(3-lithiopropyl)-l-aza-2,5-disilacyclopentane as the initiator and amine generator, and 4-bromo-l,l,l-trimethoxybutane as a terminator and carboxylic acid generator. Characterization studies of the intermediate materials as well as of the final cyclic terpolymer revealed high molecular and compositional homogeneity. Additional proof for the formation of the cyclic structure was provided by the lower intrinsic viscosity found for the cyclic terpolymer compared to that of the precursor. 

A systematic comparative study of triblock terpolymers in the bulk and thin-film state was carried out on polystyrene-fo-poly(2-vinyl pyridine)-b-poly(ferf-bulyl methacrylate), PS-fr-P2VP-fr-PfBMA. A diblock precursor with a minority of PS leading to a double gyroid structure was used. Upon increase of PfBMA content this morphology changed from lamellae with... 

Addition of the middle B block to an ABC triblock terpolymer has been investigated by Suzuki et al. for the PI- -PS- -P2VP system [ 159]. Starting from the lamellar structure of the unblended triblock (0ps = 0.42) PS homopolymer was subsequently added. At fas 0.50 a morphological transformation into a gryoid structure is observed. Even if the volume fraction of PS is increased up to fas = 0.60, the cell size of the gyroid structure will remain... 

A polymer is a large molecule (macromolecule) constructed from many smaller structural units called monomers. When only one species of monomer is used to build a macromolecule, it is known as a homopolymer, two species a copolymer, three species a terpolymer. 

---