Blending, reactive

FIGURE 15.4 SEMs of impact-fracture surfaces of PLA/starch blends (ratio 70/30) containing 1% MDI distributed in different phases (a) reference PLA/starch blend without MDI (b) PLA/ (starch + MDI) and (c) (PLA + MDI)/starch [45]. 

PLA phase, which exhibited improved interfaces between the PLA and starch, the starch may have acted as a nucleating agent for PLA, resulting in lower Tc values. For the Tm of PLA, it is interesting to note that the major discernible 

The torque variation of blends during compounding can also indicate effect of MDI distribution. As expected, the addition of MDI increased the torque of pure PLA, due to molecular weight increase [45]. Similar results for other polyesters such as polycaprolactone (PCL) and poly(butyl-ene succinate adipate) (PBSB) have also been observed [44]. The highest torque values were recorded for the blends where MDI was distributed in the PLA phase, which further confirms the benefits of PLA phase distribution of MDI. The results of a detailed study of the rheological properties of the various blends will be reported in a separate paper. 

Recently, Wang et al. [16] reported preparation of PLA/starch blends by one-step reactive extrusion. In the presence of dicumyl peroxide, the compatibility of thermoplastic dry starch (DTPS)/PLA blends, using MA as compa- 

Biodegradable Polymer Blends and Composites from Renewable Resource, Wiley, New York, 2008. 

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II. TECHNOLOGY FOR SOME PROCESS REACTIVE BLENDS PREPARATIONS... 

In multiphase polymeric systems, the properties of the end products do not solely depend on the properties of the pure components, but other various parameters also have a great impact (Fig. 1). In order to emphasize these factors, the following systems are taken into consideration (I) elastomer toughened styrene system, (2) elastomer toughened polycarbonate blends, and (3) direct reactive blend processing. 

Figure 11 Force displacement curves of a-PP, b-nonreac-tive PP-NBR blend, c-reactive blend containing 13 wt% GMA functionalized PP, and d-reactive blend containing 25 wt% GMA functionalized PP. Source Ref. 73.

TPEs prepared from rubber-plastic blends usually show poor high-temperature properties. This problem could be solved by using high-melting plastics like polyamides and polyesters. But, often they impart processing problems to the blends. Jha and Bhowmick [49] and Jha et al. [50] have reported the development and properties of novel heat and oil-resistant TPEs from reactive blends of nylon-6 and acrylate rubber (ACM). The properties of various thermoplastic compositions are shown in Table 5.4. In this kind of blend, the plastic phase forms the continuous phase, whereas... 

Elastomer blends in which the components react (reactive blending) with each other provide the best route to obtain a homogeneous product with improved physicals. The negative free energy... 

A remarkable reduction in PA-6 crystallinity was noticed after reactive blending for most of the products. In one particular case the PA-6 crystallinity was reduced from 47% to 7%. For most of the blends prepared, of the PA-6 phase could not be observed. These results suggest that the PA-6... 

Jha, A. and Bhowmick, A.K., Thermal degradation and ageing behaviour of novel thermoplastic elastomeric nylon-6/acrylate rubber reactive blends, Polym. Degrad. Stab., 62, 575, 1998. 

Haralabakopoulos, A. A., Tsiourvas, D. and Paleos C. M., Chain extension of polyethylene terephthalate) by reactive blending using diepoxides, J. Appl. Polym. Sci., 71, 2121 (1999). 

As discussed at the onset, this study was focused on determining the reactivity interaction of two lactam derivatives with acrylates in a variety of systems ranging from simple monomer to more complex mixtures. The definition of such interplay allows us to derive a simplistic scheme for the formulation of fully reactive blends containing NVP as a reactive monomer. The data show that ... 

Note 1 Examples of reactive blending are (a) blending accompanied by the formation of a polymer-polymer complex, (b) the formation of block or graft copolymers by a combination of radicals formed by the mechanochemical scission of polymers during blending. 

Note 2 Reactive blending may also be carried out as reactive extrusion or reaction injection molding (RIM). 

Brookfield, Ct., 2002, Session II, p.47-54, 27cm, 012 SEQUENTIAL REACTIVE BLENDING/ FOAMING OF PET IN EXTRUSION EQUIPMENT... 

Developments by BASF in high-impact propylene copolymers produced by reactive blending, random propylene copolymers, glass fibre-reinforced PP composites and PP foams are reported. Properties and applications of these materials are described. 4 refs. BASF AG... 

Fig. 9 Plausible representation of morphology evolution of reactive blending of immiscible and miscible blends...

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