Blend mechanical properties

A surface is that part of an object which is in direct contact with its environment and hence, is most affected by it. The surface properties of solid organic polymers have a strong impact on many, if not most, of their apphcations. The properties and structure of these surfaces are, therefore, of utmost importance. The chemical stmcture and thermodynamic state of polymer surfaces are important factors that determine many of their practical characteristics. Examples of properties affected by polymer surface stmcture include adhesion, wettability, friction, coatability, permeability, dyeabil-ity, gloss, corrosion, surface electrostatic charging, cellular recognition, and biocompatibility. Interfacial characteristics of polymer systems control the domain size and the stability of polymer-polymer dispersions, adhesive strength of laminates and composites, cohesive strength of polymer blends, mechanical properties of adhesive joints, etc. 

ETHYLENE-STYRENE INTERPOLYMER FOAM BLENDS MECHANICAL PROPERTIES AND SPORT APPLICATIONS... 

PA-6-66 copolymer (35)-NBR (65) vulcanizate) (50) / (PP(50)-EPDM(50) vulcanizate) (50) / PP-MA (10) internal mixer at 220°C / PA + rubber vulcanization and PP + rubber performed in separate steps before blending / mechanical properties vs. use of unfunctionalized PP / comparison to use of functionalized PP in initial vulcanizate / PP-f-carboxymethyl maleamic acid Coran et al., 1985... 

Addition of up to 20% of WG to PVA (WGP90, WGP80) increased the El from 211% for pure PVA up to 257% for WGP80 and reduced UTS and YM, as reported in Table 4. This behavior can be attributed to the plasticizing effect of glycerol present in WG. At higher amount of WG in the blends, mechanical properties approached the values recorded for pure WG. 

Methods of copolymer and blend preparation have been detailed elsewhere (6). The physical and mechanical properties of those polymers whose blend mechanical properties are reported here are summarized for convenience in Table I. 

PLA/poly(butyleneadipate-co-terephthalate) (PBAT) blends can be prepared with varying tetrabutyltitanate (TBT) through melt-extrusion [33]. A twin-screw extruder was used to obtain the blend. Mechanical properties, such as tensile strength, elongation at break, toughness, and stiflhess of PLA/PBAT blends can be improved significantly by the incorporation of TBT [33]. 

PEN/LCP Melt blended/mechanical properties/DSC/ DMA/SEM/evidence for transreaction between PEN and PET segments of LCP Xie et al. 2001b... 

Improved properties of commingled plastics via blend modification by reactive functionalization and compatibilization have been reported by several workers (58,65). This work is confined to a two-phase PE-PP morphology. In the two-phase immiscible PE-PP system, poor interfacial adhesion results in poor blend mechanical properties. The lack of stability in the morphology causes gross separation or stratification during later processing or use. Block and graft copolymers of the form A-B have been used as compatibilizers to improve interfacial adhesion and reduce interfacial tension between A-rich and B-rich phases to provide A-B alloys with improved and unique balances of properties. 

The Box-Behnken Statistical Design is shown in Table 5.2. Material-related input variables (HDPE fraction, Kraton rubber concentration) and processmixing-related input factors (screw speed, in revolutions per minute) and their design ranges are shown in Table 5.3 and 5.4, respectively. Responses of interest are compounded blend mechanical properties and overall conversion costs. 

Some industrial or laboratoiy attempts are based on reprocessing at low temperatirres. In these attempts high melting polymers are used as sohd filt ers." Another useful method comprises the use of compatibilizers and stabihzers in the pol3rmer blends. Mechanical properties of these recycled mixed plastics are generally inferior, the sruface properties are poor, and in some cases the cost of compatibihzers and stabihzers is too high for recycled materials. 

Different compositions of wheat thermoplastic starch (TPS) and polycaprolactone (PCL) were melt blended by extrasion and injected [104]. It was noticed that the addition of PCL to the TPS matrix allowed the weakness of pure TPS to be overcome low resilience, high moisture sensitivity and high shrinkage, even at low PCL concentrations, e.g. 10 wt%. However, a fairly low compatibility between both polymeric systems was reported. For PCL-based blends, mechanical properties depend both on plasticization level and PCL content (Table 3.22). 

PLLA/PDLLA blends with different concentration of surfactant, mechanical properties of PLLA/PDLLA/2% surfactant blends, mechanical properties of PLLA/PCL blends and mechanical properties of PLLA/PCL/2% surfactant blends are shown in Table 4.8 - 4.16, respectively. 

Mao, L., Imam, S., Gordon, S., Cinelli, P, and Chiellini, E. Extruded comstarch-glycerol-polyvinyl alcohol blends Mechanical properties, morphology and biodegradability. Journal of Polymers and the Environment, 8, 205-211 (2002). 

Zhang, Z., Chen, S., Zhang, J., Li, B., and Jin, X. (2010) Influence of chlorinated polyethylene on poly(vinyl chloride)/poly (a-methylstyrene-acrylonitrile) blends Mechanical properties, morphology and thermal properties. Polym. Test., 29, 995-1001. 

These actions combine to drastically improve blend mechanical properties and are shown schematically in Fig. 9.4. The photomicrograph in Fig. 9.5 shows a blend of PS, LDPE, and PMMA and dramatically demonstrates the effect compatibilization has on the morphology. 

S/Ch membrane Blend Mechanical properties and antimicrobial activity Liu et al., 2009a... 

---