PVC/PMMA

It should be noted that by immobilizing the metal complex catalysts on carbochain polymers it is possible to prepare polymer-polymer compositions using PVC, PMMA, poly(vinyl acetate), etc., as the polymeric fillers [286-287]. 

Figure 17 Comparison of XPS (left) and FT-IR PVC images for two different PVC/PMMA blends with constant PVC molecular weight and PMMA molecular weight 75 kDa (a) and 838.3 kDa (b), respectively. Reproduced from Artyushkova et al. [93], with permission of the Society for Applied Spectroscopy. 2000.

Recent developments have allowed for more detailed studies of polymer surface morphology by ESCA. Angle-resolved ESCA (ARXPS) allows for providing chemical compositions from shallower depths. By varying the angle of incidence different depths can be probed, and procedures have been developed to arrive at three-dimensional reconstruction of the surface. An example is shown in Figure 2, where a PVC/PMMA polymer blend has been analysed using such an approach [9]. 

Figure 2 Volume visualization of the three-dimensional volume representing the PVC-enriched phase of the polymer blend (a) the whole volume rendered, (b) three orthogonal slices showing the interior of the volume, (c) single isosurface showing 5/95 PVC/PMMA composition of the blend, and (d) multiple isosurfaces displaying three compositions 5/95, 12/88, and 22/78 of the blend. Reproduced from Artyushkova and Fulghum [9].

Figure 4.16 Melt densities for select resins as a function of temperature. PVC, PMMA, and PVDF resin data are from Zoller and Walsh [43]. All resins contain only extremely low level of additives...

Secondly, a series of linear, well-characterised polymers (PVCs, PMMAs, PVAcs and polysulphone) were analyzed and their MWs by SEC compared with those quoted by the supplier. 

Comparison of MW Data from Suppliers with Those Calculated from the Narrow-PS Calibration for Linear PVCs, PMMAs, PVAcs and Polysulphone... 

Artyushkova, K., Wall, B., Koenig, J. and Fulghum, J. E. (2000) Correlative spectroscopic imaging XPS and FTIR studies of PVC/PMMA polymer blends. Appl. Spectrosc. 54(11), 1549-58. 

Fully amorphous polymers may be transparent, such as PVC, PMMA, PC and PS. They can, in principle, be applied in the optical industry for spectacles, simple photographic lenses etc. For precision optics they are less suited, since because of volume retardation as well as by the fact that they are often manufactured by injection moulding, they cannot meet the requirements of narrow dimension tolerances. Moreover, their low resistance to scratching is a disadvantage in optical applications. 

Carbanions can react with Cl in PVC macromolecules [295] and with the ester group of PMMA [284]. The rates of the two reactions are probably not very different by the addition of a-methylstyrene tetramer dianion to a PVC + PMMA solution, the copolymer poly(vinyl chloride)-gro/ir-poly-(methyl methacrylate) was obtained [296]. Macrocations formed by the reaction of strong acids with polyalkenes (see Chap. 3, Sect. 3.2) react with polyethers (polysiloxanes) yielding graft and block copolymers, e. g. poly(propylene)-0ra/ir-poly (oxyethylene) [297], poly(propylene)- /ocA -... 

Physical properties were evaluated using standard DIN or ASTM specifications. The sealants were filled into Teflon molds to form homogeneous test pieces of comparable thickness. The specimens were then moisture cured and conditioned at 25 °C and 50% relative humidity for 14 days before mechanical property testing. The hardness of the cured sealant samples was measured by Shore A. Shelf life at 50 °C was determined for a maximum of 21 days. Tack-free times were determined by finger touch under ambient conditions. For adhesion testing the substrates were first wiped with either methyl ethyl ketone (aluminum, steel, glass, concrete, wood) or methanol (PVC, PMMA, ABS, polystyrene), then washed with detergent, rinsed with distilled water, and allowed to air dry prior to preparation of the test specimens. Specimens were cured for 14 days at ambient conditions. 

DISTANCE PROM PETRI GLASS SIDE (ptn) Fig. 3 The change in PVC content in thichness direction of PVC/PMMA blend. 

In the case of PVC/PMMA system, we prepared samples by changing the above 4 controllable conditions, and examined the graded structures of those samples by FTIR-ATR, Raman... 

Fig. 4 DSC curves of several types of PVC/PMMA graded blends.

Physical properties of PVC/PMMA blend containing graded structure 2 (an extremely wide graded concentration), in comparison with those of blend containing graded structure /(similar to a laminate system), perfectly miscible blend(5/5), PVC only and PMMA only, were summarized in Table 2. 

Historically, blending was used to improve impact strength of the early resins, i.e., toughening of PS, PVC, PMMA, PET, PA, etc. With time, blends evolved into multi-polymer systems, that not only have to be impact-modified, but also compatibilized. Many blends have been formulated with a multicomponent modifier that simultaneously compatibihzes and impact-modi-fies the mixtures. 

The parameter ji defined in Eq 2.81 is a measure of the polymer-polymer miscibility — negative values indicate immiscibility, positive the miscibility. Three series of blends were examined (1) PVC/PMMA, (2) PiBMA/PMMA, and (3) PiBMA/PVC. In agreement with the calculated values of the parameter the first of these three blends was found miscible, whereas the two other immiscible in the full range of composition. However, the method is, at best, qualitative. For example, the effect of solvent on the parameter was not investigated, but fundamentals of intermolecular interactions make it dubious that non-polar and strongly polar solvents will lead to the same value of the parameter The author observed that the method breaks down for polymer pairs that form molecular associations. Intrinsic viscosity measurements were also used to evaluate intermolecular interactions in blends of cellulose diacetate with polyvinylpyrrolidone [Jinghua et al, 1997]. 

Since blends are mainly used as structural materials, the most important properties are mechanical, especially the impact strength, stiffness, and elongation. Historically, blending was developed to improve these properties in the early resins, viz. PS, PVC, PMMA, PET, PA, etc. When blending started to involve mixtures of polymers, the impact modihcation has progressively changed into compatibilization. However, even today, many blends proht from the simultaneous compatibilization and impact modification by addition of multicomponent modifiers. Many patents and papers in the open literature address this question, some of which will be presented in this section and the following one on patented blends. 

Limera is a family of styrenic thermoplastic/ rubber compositions. The compositions are suitable for compounding with a variety of additives, fillers and polymers such as PS, PVC, PMMA, ABS and PPE. They are processable by injection molding, extrusion and blow molding. 

SAN these blends are miscible. Commercial grade PVC, PMMA, and SAN were used as-received (Table 11.9). Polymer blends were made by using an internal mixer. Very thin samples (100 to 200 nm thick) were cut at room temperature using an ultramicrotome. The samples were mounted on copper or nylon grids and coated on one side with 5 to 20 nm of carbon to reduce charge and shrinkage during irradiation in the electron microscope. 

In the PVC/PMMA blend, the chlorine and the mass loss of the PVC increased in the presence of PMMA. Similarly, in the PVC/PCL blend also... 

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