Impact modifiers, analysis

On the whole, GPEC remains a technique in search for polymer/additive applications with real added value [835]. Practical applications of GPEC may be found in the analysis of polymer blends [836], laminates and packaging materials. For example, the technique can be used for determination of the impact modifier content in PS packaging material, which contains a soluble transparent rubber for transparent applications,... 

On-line SFE-GC-MS was used for the analysis of organic extractables from human hair [312]. Van Lieshout et al. [313] described GC-MS analysis of an SFE extract of an (ABS) impact-modified PC/PBT blend identifying Ionol CP, Dressinate, cyclic PBT trimer, Irganox 1076 and Irganox PS 800. TD-GC-MS was used in the development of flame retardants, and for the analysis of fire debris [314]. The application of laser desorption fast GC-MS analysis was employed in the analysis of DOP on a stainless-steel surface [221]. 

STUDY OF ADDITIVE COMPATIBILITY WITH POLY(VINYL CHLORIDE). I. DYNAMIC MECHANICAL ANALYSIS (DMA) OF IMPACT MODIFIED RIGID PVC CONTAINING ESTER LUBRICANTS... 

Since polysulfone is often melt processed at high temperatures (up to 370°C), another requirement of a successful impact modifier is that it display adequate thermal stability at these temperatures. As expected from the known good thermal stability of polysulfone and silicones (10, 11), the PSF/PSX block copolymer displays excellent thermal stability. This is illustrated by the thermogravimetric analysis curves shown in Figure 6. 

Polymer-based multicomponent systems are abundant in many applications. The properties and performance of particulate-filled systems, such as elastomers and impact modified polymers, and also polymer blends, block copolymers, and fiber reinforced systems, depend to a large extent on the distribution of the components. Hence the local analysis of these distributions down to sub-100 nm length scales (dictated, e.g., by the size of primary filler particles) is of considerable significance. Materials contrast in several AFM approaches offers the possibility to address these issues directly at the surface of specimens or on bulk samples that have been prepared correspondingly. 

Solid-state NMR has been applied successfully in a few cases for the study of poly(imide) blends. It can be said, however, that the techniques arising from recent advances in the analysis of polymer blends, such as selection techniques based on multipulse methods, and improvements in the modelling methods of spin diffusion, have yet to be applied to the study of blends containing poly(imide)s. It is suggested that these techniques will have an important role to play in future studies of poly(imide) blends, particularly for blends such as impact-modified BMI resins. 

The approach most commonly adopted is to first incorporate carbon-black and then compensate for the lost impact strength and breaking strength by means of impact modifiers. In most cases this makes the compounds too soft (though still inelastic) or too brittle [30a-m], Optimisation is either a balancing act or requires analysis of the interactions in the dissipative structures [29], The aim is to obtain, despite the... 

This paper outlines procedures used in the identification of typical PVC formulations, starting with the resin and proceeding to impact modifier, process aids, lubricants, stabiliser system and fillers. The emphasis is on FTIR microscopy as the most versatile approach requiring small samples and minimal to no sample preparation. Other commonly used FTIR techniques are also outlined. Wet separation protocols, applicability and limitations as related to FTIR analysis are discussed. Typical examples include vinyl siding, packaging and bottle formulations as well as contaminants often encountered in these formulations and raw materials. 

Figure 18.49 Prediction of polymer impact resistance. Comparative dynamic mechanical analysis profiles for a series of impact modified polypropylenes. Source TA Instruments, New Castle, DE, USA)...

Another blend, also invented at General Electric, is Xenoy . This is an immiscible blend of polybutylene terephthalate (PBT) and polycarbonate (PC) [5,6]. This blend is immiscible it has separate phases of PBT and of PC. An immiscible blend is characterized by two distinct Tgs and thermal analysis of this blend shows the Tg of PBT and of PC as well as a sharp melting point for the crystalline PBT. The blend also includes an impact modifier. It exhibits the good impact associated with PC and the solvent resistance associated with PBT. Because of these properties, it is suitable for applications such as automotive bumpers requiring high impact and gasoline resistance. 

Pyrolysis techniques are particularly suited for the more difficult polymer/additive analysis problems on account of intricate architecture and morphological features, e.g. in case of (i) polymer-bound additive functionalities (AOs, FRs) (ii) impact modifiers such as terpolymers (e.g. styrene-hydrogenated butadiene-styrene), graft polymers (e.g. EPM-g-PBT) and an internal rubbery phase in core/shell polymers (e.g. acrylate-based cross-linked polymer) [527] and (Hi) interfacial agents (e.g. graft copolymers, sizings). 

Low-field low-resolution NMR is extensively being used both for process and quality control of polyolefins [198] and blends e.g. ABS/PC), but less so for additive dosing and monitoring. LR-NMR has limited use for polymer/additive analysis. If any, given the detection limits, LR-NMR is most suited for additives present in relatively high percentage levels such as plasticisers, flame retardants, impact modifiers, fillers, or lubricants, and does not reveal antioxidants, UV stabilisers, etc. 

In PVC technology certain polymeric additives can be considered as process aids. These polymers have a similar composition to those used as impact modifiers in PVC formulations but are more compatible and so are primarily included to ensure more uniform flow and hence improve surface finish. Such process aids include ABS, chlorinated polyethylene, MBS, EVA-PVC graft polymers and acrylate-methacrylate copolymers. As these are usually found in unplasticised PVC, direct analysis of the product by IR will usually indicate the presence of those that have a distinctive spectmm as no masking by plasticiser will take place. However, even rigid PVC can contain a small amount of phthalate and so it is advisable to carry out a solvent extraction to clean up the matrix first. Where the process aid (e.g., chlorinated polyethylene) has a relatively bland spectmm, a technique such as NMR will be required to both detect and quantify it. NMR will usually be required to quantify the other types as well, unless the spectrum is very distinctive and standards of known composition are available. 

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