End use performance

D. R. Ireland, in R. E. Evans, ed.. Physical Testing ofPlastics-Correlation with End-Use Performance, ASTM STP 736, ASTM, Philadelphia, Pa., 1981, pp. 45-58. 

The three types of rosin perform differently because of different distributions of resin acids, as well as different types and quantities of impurities. These differences are reflected in end-use performance. 

To improve the end use performance and make the processability easy, control of MW and MWD as well as the use of.more than one comonomer has been reported for LLDPE [28]. Union Carbide s high MW-LLDPE with broad MWD is a 1-hexene-based resin, and its film provides superior (about 30-50% higher) tensile strength, puncture resistance, and dart impact strength than conventional 1-hexene-based resin, but with lower tear resistance in the transverse direction. The broad MWD makes the resin processability easy on the conventional extruder. 

MW and MWD are very significant parameters in determining the end use performance of polymers. However, difficulty arises in ascertaining the structural properties relationship, especially for the crystalline polymers, due to the interdependent variables, i.e., crystallinity, orientation, crystal structure, processing conditions, etc., which are influenced by MW and MWD of the material. The presence of chain branches and their distribution in PE cause further complications in establishing this correlation. 

A typical balance of processability and end use performance is the general requirement of polymeric resins. The studies on the different polymer fractions have provided a great support in tailoring the MW and MWD in order to achieve the required properties and eliminating the unwanted molecular species. The increase in low-... 

Table 21.2 provides a general guide to the effect that chemical constituents can have on unsaturated polyester resin end-use performance. The routes to change an unsaturated polyester resin for a particular application is normally apparent and there can be several pathways available to achieve the desired properties. As the unsaturated polyester resin markets are highly competitive, raw material cost usually reduces the number of available routes available to the formulator. As noted previously, there are three main types or families of unsaturated polyesters, namely general purpose orthophthalic, isophthalic and DCPD resins. However, within each of these families, there are hundreds of variants that incorporate these various chemical constituents in different combinations and permutations to achieve the desired results. 

The quality and properties of recyclate should be comparable to those of virgin resins. Therefore, upgrade of recycled materials might be necessary in order to improve their properties. Clearly the effect of polymeric contaminants on the end-use performance of recyclate is an important issue, and the amount of contaminants that can be tolerated depends on the final application. Polymeric contaminants do not only pose a threat for environmental impact but also impact the ultimate tensile elongation behaviour [12, 13]. 

The properties of polymers prepared by different process can be studied in a variety of ways, the choice often depending on the intended end use of the polymer. For coatings applications, mechanical testing of films can lead to an understanding of polymer structure as well as to a prediction of end use performance (5). 

In the world of plastics, the end-use performance of the technically used materials counts, as well as their behaviour in the various processing operations in which they are transformed into finished articles. 

Enhance, Green Chemicals and Biopolymers From Rapeseed Meal With Enhanced End-Use Performance, Final report of EU-funded Enhance project QLK5-1999-01442 (2003). EPOBIO, Oil Crop Platforms for Industrial Uses, CPL Press, Newbury, UK (2007). 

The results reported herein indicate that hydrodynamic chromatography is an accurate, reproducible technique for latex particle size distribution analysis. Typical analysis requires 15-20 minutes to complete and reproducibility is generally better than 5% for both reported particle size and mass percent. Latex particle size distributions found using HDC provide useful information about end use performance of many types of material (see Table V). 

In addition, a great need exists for improved test procedures to predict end-use performance. The correlations between accelerated exposure devices and normal fluorescent lamps, described in this report, represent only a preliminary effort to refine and establish meaningful laboratory methods for evaluating light stabilizers. Exposure data from a greater number of samples, containing a greater variety of formulations, are needed for more accurate correlations. 

The comparative chemical cleanliness, residual contaminant level, and control over the properties of carbon blacks produced through the furnace process cannot be overstated. Carbon blacks containing high levels of residue and chemical contamination may adversely affect end-use performance. For plastics used in sensitive applications such as fiber and for some engineering resin formulations, raw material specifications require low levels of chemical and residual contaminants. 

Polymers are typically complex mixtures in which the composition depends on polymerization kinetics and mechanism and process conditions. To obtain polymeric materials of desired characteristics, polymer processing must be carefully controlled and monitored. Furthermore, one needs to understand the influence of molecular parameters on polymer properties and end-use performance. Molar mass distribution and average chemical composition may no longer provide sufficient information for process and quality control nor define structure-property relationships. Modern characterization methods now require multidimensional analytical approaches rather then average properties of the whole sample [1]. 

Friction material technology has gradually evolved over the past century driven primarily by increasing demands on end-use performance or environmental considerations. The recent introduction of FMVSS... 

Computer-aided engineering applications have been developed to optimize the molded part design with respect to manufacturing and end use performance. Many, if not most, commercial molding applications utilize mold filling analyses to analyze the melt flow and pressure distribution in the injection mold before the mold is manufactured. Typically, these analyses... 

The most significant aspect of a well-designed fiber-reinforced composite is that its end use performance may be predicted from the properties of each constituent.f In recent years. Quality by Design and Design for Six Sigma have advocated a set of predictive methodologies and protocols that ensure the delivered goods meet the market demands. Elastic constants can be predicted for continuous reinforced... 

With advances in computer technology in recent years, simulation has often provided a very powerful tool to predict the end-use performance from the selected component properties and to establish structure-performance relations with a certain degree of confidence. This approach has been termed in silico design as opposed to in vitro or in vivo. " In silico experimentation - the ability to explore simulations rapidly reduces the need for in vivo experimentation slow, multiple iterations of trial and error for design of new composite structures. The combination of design tools and computer modeling will drive development of new thermosets, with improved performance. This includes new structures based on known materials and the development of new chemistries for selected applications. 

Preceding sections summarized the physical and chemical nature of VI improvers and the lubricants containing them this section links those features to end-use performance properties. Since engine oils are by far the largest market for VI improvers, this application is the primary focus of this section. 

It is useful to be able to estimate the thermal conductivities of polymers, both for optimizing certain processes and for evaluating end-use performance ... 

Recently, we reported (1, 2) a new class of high strength/ high modulus fibers prepared from all-p-phenylene oxadiazole/ N-methyl hydrazide copolymers. Oxadiazole homopolymers and fibers had been described earlier by Iwakura (3), Imai (4), and Frazer (5). All-p-phenylene oxadiazole/N-methyl hydrazide copolymer fibers were shown by us to give tire cord with excellent end use performance including good fatigue characteristics. In concurrent... 

In another example, ] a problem with poor physical properties of molded fluoroplastics was overcome. Transfer molded material was found to have low modulus of elasticity above 150°C and was prone to irreversible cold flow. The solution involved embedding a metal or plastic insert as a core material in the mold. The choice of the core material depended on the end use performance requirements. 

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