Compatibilization process

In addition to the abovementioned parameters, various factors such as viscosity of the copolymer and its interaction with the homopolymers also play a major role in the compatibilization process. 

PC/ABS with EAA acidic compatibilizer processability and impact strength Grigo ei al., 1984... 

In this chapter, compatibilization of polymer blends by means of addition of a compatibilizer will be discussed. First, the theories will be summarized of the (i) interface, (ii) interphase, and (iii) compatibilization process. This brief summary is to provide a general framework for understanding the phenomena associated with compatibilization, and guidance for optimization of the process to gain maximum performance. 

The majority of commercially important, immiscible polymer blends rely for compatibilization on the presence of a copolymer of the blended polymers. Nowadays, such a copolymer is almost never synthesized in a separate step and then added as a distinct entity to the blend of immiscible polymers. Instead, a compatibUizing copolymer is most economically formed simultaneously with generation of interphase morphology during extrusion processing, a process referred to as Reactive Compatibilization. The Reactive Compatibilization process is logically a sub-category of the broader class of Interchain Copolymer Formation reactions performed by Reactive Extrusion [Brown, 1992],... 

This chapter attempts to classify the specific copolymer architectures formed by the different chemical reactions that have been described in the open literature for Reactive Compatibilization processes. The emphasis is on illustrating the scope of these particular reactions, and not on presenting every known example of a particular compatibilization strategy. 

Reactive Compatibilization process for reasons discussed below. 

It is to be hoped that fumre work on Reactive Compatibilization will combine the excellent materials science that has been done to date with additional considerations of the chemical processes occurring. Such knowledge of the chemistry, coupled to fluid mechanics and morphology development models, would provide a powerful tool for optimization of known and invention of new Reactive Compatibilization processes to prepare commercially valuable polymer blends. 

Reactive processing combines fine polymer chemistry with polymer processing. Thus, development of the reactive compatibilization process involves ... 

During the development stage, it is essential that samples are frequently taken from the extruder and analyzed for the extent of reaction as well as for the morphology and the key properties. (The sampling methods are discussed in Part 9.2.1.2 Morphology evolution in an extruder). It may also be profitable to verify the whole reactive compatibilization process by the carcass method. 

The purpose of these simulations is to evaluate the importance of copolymer sequence distribution on its ability to compatibilize a biphasic interface. Thus, an understanding of the compatibilization process is necessary to decide how this ability can be analyzed. The added copolymer is thought to act as a polymeric surfactant in that it migrates to the biphasic interface of a phase separated blend and lowers the interfacial... 

Compatibilization Process of modification of the interfacial properties in immiscible polymer blend, resulting in reduction of the interfacial tension coefficient and stabilization of the desired morphology, thus leading to the creation of a polymer alloy... 

Interphase a nominal third phase in binary polymer alloys, engendered by interdiffusion or compatibilization at the interfaces between the two polymer domains. The interphase thickness A/ varies between 1 and 60 nm depending on polymers miscibility and compatibilization Compatibilization process of modification of the interphase in immiscible polymer blends, resulting in reduction of the interfacial energy, development, and stabilization of a desired morphology, leading to the creation of a polymer alloy with enhanced performance ... 

In this chapter, compatibilization of polymer blends by means of the addition of a compatibilizer will be discussed. First, the theories will be sunnnarized as follows (i) interface, (ii) interphase, and (iii) compatibilization process. Reference to some recent work in the area will also be performed in this updated version. This brief summary is to provide a general framework for understanding the phenomena associated with compatibilization and guidance for optimization of the process to gain maximum performance. The theoretical part is followed by the experimental part, where the methods for the determination of interfacial properties are presented. Most of the chapter is dedicated to provide comprehensive information on the characteristic properties of blends compatibilized by the addition of a compatibilizing agent, also with updates from recent literature. 

The coverage of this chapter is arranged by binary polymer Blend Type, in alphabetical order of the first polymeric component. Thus, polyamide blend is the first category discussed herein. Subcategories within each Blend Type category are arranged by the specific chemical reactions that have been described in the literature for reactive compatibilization processes. 

Generic Processes and Specific Types of Reactions to Form Copolymer in a Reactive Compatibilization Process... 

In this chapter, the preparation and properties of polyolefin-based NFC with special reference to the types of fibers, compatibilization, processing methods, mechanical properties, and some applications will be discussed. 

COMPATIBILIZATION, PROCESS, AND ECONOMIC ANALYSES OF RECYCLED PP-HDPE BLENDS... 

Simple addition of a compatibilizer to a mixture of polymers has the disadvantage of high costs. The extrusion compatibilization process, as described here, has the advantage that the copolymer is formed during the mixing process and no extra process step is necessary. 

Keywords polymer blend, liquid crystalline polymer (LCP), morphology, compatibilization, processing, polymer reinforcement, in situ composites. 

Asymmetric double cantilever beam and peel test experiments were completed by Eastwood et al. (Eastwood and Dadmun, 2002) to evaluate the ability of multiblock or blocky distributed chlorinated polyethylenes (bCPEs) to strengthen the PVC/POE interface compared to that of randomly distributed chlorinated polyethylene (rCPE). Additionally, the dependence of molecular weight and chlorine content of the bCPE (composition) will be evaluated to ascertain the influence of these parameters on the compatibilization process. Chlorinated polyethylenes to compatibil-ize poly(vinyl chloride) (PVC) and polyolefin elastomer (POE) blends. A series of chlorinated polyethylenes that are blocky in nature (bCPEs) with varying composition (% chlorine), and molecular weight (melt index) were used for this experiment. 

The rate determining step in the compatibilization process when adding a third component is the synthesis of new copolymers or new functionalized polymers able to induce binding between the incompatible polymers. Some commercially available materials are reported in Table 4. 

Figure 6.22 compares the performance of the one-step and two-step reactive compatibilization processes. The one-step process corresponds to screw profile B3. In order to make the comparison meaningful, the two-step process uses the same screw profile as the one-step process. Moreover, the composition of the free radical grafting system is the same for both processes, namely, PP/MA/styrene/peroxide = 100/1.5/1.6/0.3 by weight. In this way, the amount of grafted MA onto PP is the same (0.5 phr) in both processes. Five different PP/PA6 (80/20) blends are made using the two-step process in which the PP phase contains 0,20,40,60 or 80wt.% PP-g-MA. The rest of the PP phase is composed of an inert PP (the inert PP used has better mechanical properties than that used for the experiments in Fig. 6.21). The same number of PP/PA6 (80/20) blends is obtained using the one-step process. In order for the blends obtained with the one-step process to have the same compositions (the inert PP, PP-g-MA and PA6) as those obtained with the two-step proeess, the feed rates at the first and second hoppers for different chemicals are adjusted accordingly. Results show that the compatibilization perfonnance of the one-step process is quite similar to that of the two-step process. For example, none of the blends...

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