Acrylic Modifier Research Articles

Comparison of toughening effects of several common toughening agents and polycarbonate‐polydimethylsiloxane block copolymer on polyvinyl chloride

AbstractIn this work, different toughening agents such as chlorinated polyethylene (CPE), acrylonitrile–styrene‐acrylate (ASA) terpolymer, acrylic modifier (ACR, the main component is poly(methyl methacrylate‐butyl acrylate)) and polycarbonate‐polydimethylsiloxane block copolymer (PC‐b‐PDMS) were used to toughen polyvinyl chloride (PVC). Different content toughening agents (10 and 20 phr) were added into PVC and their properties were tested. The results exhibited that ACR, ASA, and PC‐b‐PDMS‐40 (40% PDMS content) had high impact strength (more than 100 kJ m−2) at room temperature. With the decrease of temperature, the toughening effect of ACR and ASA dropped significantly (7.30 and 3.69 kJ m−2 at −30°C respectively), while PC‐b‐PDMS‐40 still had certain toughening effect (19.66 kJ m−2 at −30°C). The tensile and flexural strength of blends decreased with the addition of toughening agents, while due to strong interactions between PC and PVC, elongation at break of PVC/PC‐b‐PDMS also have obvious drop. Heat distortion temperature results showed that the heat resistance of PVC was not reduced by toughening agents except CPE. The DMTA curves of blends revealed the reason why PVC/PC‐b‐PDMS‐40 had good toughness at low temperature that the glass transition temperature of PDMS is very low (−123°C), which makes it flexible at low temperature.

ACRYLIC OLIGOMER BASED ON BUTADIENE DIMER FOR ANTI-CORROSION SURFACING

Statement of the problem. The objective of the work was to assess the effectiveness of the modifying effect of the 4-vinylcyclohexene co-oligomer with methyl methacrylate (OBMMA-50) on the properties of an anticorrosion coating based on KORS copolymer obtained using styrene rectification residues to increase the technological and operational physical and mechanical characteristics of the initial coating. Results. The functional, structural and conformational features of the initial copolymer and oligomeric modifier are established, which ensure their compatibility in the formation of an anticorrosion surfacing. The optimal prescription composition and effective range of the acrylic oligomer content were revealed, where there is an increase in technological and physico-mechanical parameters of the initial anticorrosion surfacing from 15 to 100 %.Conclusions. The features in the structure and composition of the starting polymer and acrylic modifier are shown that provide a significant increase in the physical and mechanical parameters of the coating containing the optimal concentration of acrylic oligomer in its composition.

Modifiers for Rigid Polyvinylchloride Compositions of Building Purpose

A comparison of small doses (up to 0.7 mass part) of impact strength modifiers of foreign and domestic production in polyvinylchloride-based compositions is given. Domestic acrylicnitrile- butadiene styrene modifiers (ABS) were used. The developed shock-resistant polyvinylchloride compositions in the presence of ABS elastifier have high melt fluidity, which has a beneficial effect on the recyclability. Changes in supramolecular structure were estimated from thermomechanical testing and electron microscopy data for both unfilled and filled PVC samples. Thermomechanical analysis showed that the presence of ABS modifier had a favorable effect on the technological properties of PVC-based samples. Electron-microscopic images indicate that in unfilled PVC samples, the heterogeneous PVC structure is expressed in the presence of ABS copolymer in comparison with foreign acrylic modifiers. When the compositions are filled with micro-heterogeneous structure in dispersion medium, the filler-polymer is formed by chalk particles, while ABS elasticifier is at the phase interface. Due to the peculiarities of the structure ABS has a higher degree of “fixation” on the surface of the chalk particles in comparison with the basic compositions containing acrylic modifiers, which with increasing chalk concentration leads to lower wear and tear on the top of the forming equipment.

Hydrolytic stability of polycarbonate/poly(lactic acid) blends and its evaluation via poly(lactic) acid median melting point depression

The hydrolytic degradation of polycarbonate (PC)/poly(lactic) acid (PLA) blends in deionized water media first time was studied in this research. Effects of degradation on mechanical properties and elasticity of the blends was presented and evaluated. Median PLA melting point depression approach is proposed for determination of degree of degradation. The proposed technique allowed true degree of degradation estimation not subjected to numerous phenomena affecting mechanical properties like moisture absorption and crystallization. The use of median melting point of PLA allowed accounting for numerous effects of PLA degradation resulting in its asymmetric melting curve. The presence of the acrylic impact modifier in blend significantly decreased the rate of moisture absorption rate and properties deterioration at later stages of degradation. This phenomenon was attributed to limited propagation of degradation areas due to the presence of acrylic modifier droplets having hydrophobic nature. It was found that degradation of PC/PLA blends due to hydrolysis may proceed in two distinctive stages: a) water diffusion and pit formation and b) hydrolytic degradation in PLA phase where degradation was supported by water transport via pits. The second stage is accompanied by accelerated water absorption due to the hydrolysis reaction and rapid properties deterioration. It was also found that PC phase also subjected to degradation due to pH decrease caused by PLA degradation. The PC degradation by-products like bisphenol A were not detected in degraded polymer samples which was attributed to their continuous removal into surrounding water media.

The fracture mechanism of polylactic acid resin and the improving mechanism of its toughness by addition of acrylic modifier

AbstractThe fracture mechanism of polylactic acid (PLA) resin and the improving mechanism of its toughness by addition of an acrylic modifier were examined. Plane strain compression testing of PLA clearly showed strong softening after yielding. Because the stress for craze nucleation of PLA was close to the yield stress, brittle fractures resulted. The addition of an acrylic modifier to the PLA significantly lowered the yield stress and formed many voids. The release of the strain constraint because of the formation of many voids and the decrease of yield stress resulted in the relaxation of stress concentration, and the toughness was improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Impact Strength and Hardness Properties of Banana Pseudo‐Stem Filled Unplastisized PVC Composites

Specific responses of thermoplastic components are required when they are subjected to impact conditions to minimize the damage in human body. Hardness property gives material, high resistance to various kinds of shape change when force is applied. In this study, mechanical properties such as impact strength and hardness of banana pseudo‐stem (BPS) unplastisized polyvinyl chloride (UPVC) composites were determined. It was found that fibre loading of BPS filler could enhance the properties of the impact strength and hardness of BPS/UPVC composites. The results on the addition of acrylic modifier to the composites have been discussed.

Online measurement of rheological properties of PVC/wood‐flour composites

AbstractBy using a factorial design approach, this study examined the effect of the component materials on the viscoelastic properties of PVC/wood‐flour composites. Statistical analysis was performed to determine the effects of wood‐flour content, acrylic modifier content, and plasticizer content on the die swell ratio and viscosity of the composites measured online on a conical twin‐screw extrusion capillary rheometer. The viscoelastic properties of the samples also were measured using dynamic mechanical analyzer (DMA). Wood‐flour content and acrylic modifier content were the two important variables affecting the die swell ratio, whereas the addition of a low level of plasticizer did not affect this ratio. The die swell increased with the increased acrylic modifier content, but it was reduced considerably by adding wood flour into the PVC matrix. The true viscosity of neat PVC and PVC/wood‐flour composites decreased with the plasticizer content, irrespective of the acrylic modifier content. However, the addition of acrylic modifier significantly increased the viscosity of unfilled PVC, while an opposite trend was observed for the composites, owing to the differing effect of acrylic modifier on the melt elasticity and viscosity of these materials. J. Vinyl Addit. Technol. 10:121–128, 2004. © 2004 Society of Plastics Engineers.

Acrylic-fluoropolymer mixtures and their use in coatings

Fluoropolymer coatings, particularly those based on polyvinylidene fluoride (PVDF) resins, have a 35 year history of outstanding performance in outdoor applications. However, the chemical inertness of PVDF presents challenges to the paint formulator in that it prevents adhesion to substrates and makes it difficult to disperse pigments. To overcome these difficulties, an acrylic modifier resin is usually added to the PVDF resin. The acrylic modifier is traditionally physically blended with the PVDF resin to improve coating adhesion and enhance pigment dispersion. The physical blending results in a PVDF/acrylic mixture on a macro-molecular scale. ATOFINA Chemicals, Inc. has developed a novel approach to mix the fluoropolymer and acrylic on micro-molecular scale. Because of this intimate mixing, and the wide latitude of the acrylic and fluoropolymer monomers that can be utilized, a wide range of unique properties can be achieved in solvent-base dispersion coatings, and water-borne coatings. The unique properties of the solvent-base and water-borne coatings are discussed in this paper.

Modification of epoxy resins by acrylic copolymers with side-chained mesogenic units

A series of acrylic copolymer modifiers with mesogenic side chain (LCGMB) were synthesized and used to modify E-51/DDM system. The dynamic mechanical behavior and impact strength of the modified systems were investigated. The results showed that the impact strength and modulus were influenced by the composition and the amounts of the modifiers. With addition of 10% (wt %) LCGMB (molar ratio of GMA : HEMA : MMA : BA = 4 : 10 : 26 : 60) based on the amount of the epoxy resin, the modified systems obtained 100% increase in impact strength, 10% increase in modulus, and a little increase in Tg. The toughening mechanism of the modified systems was also discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1787–1792, 1999

Effect of an acrylic modifier on the brittle to ductile transition in poly(vinyl chloride)

AbstractInstrumented notched Izod measurements were made on test specimens cut from milled compression molded plaques of modified and unmodified poly(vinyl chloride) (PVC). The experimental variables were notch radius (from 0.025 to 6.35 mm in 8 steps) and two temperatures (23 and 12.5°C). Load‐time and energy‐time curves were determined under each set of experimental conditions, and each condition was replicated five times. The brittle to ductile transition is readily observed in this experimental range. The transition always occurs at shorter notch radii at each temperature for the modified PVC. In the transition region, the total energy drops from the 1,000 to 2,000 J/m range to less than 150 J/m. In this region, maximum loads remain the same while the times to break becomes much shorter for the brittle materials. These results suggest that the underlying molecular mechanism for brittle failure is the inability of the system to respond to the applied deformation. The oscillations observed in the printed output of the instrumented impact test were identified as having instrument rather than test specimen origins.

The all‐acrylic weatherable impact modifier for PVC

AbstractRigid poly (vinyl chloride), PVC, is finding increasing use in outdoor applications as a replacement for conventional materials such as wood, aluminum, steel, and other materials. Formulating PVC for outdoor applications requires special attention to several essential properties in order to achieve the high‐quality standards needed over a long period of time. One area that needs modification in a rigid PVC formulation for outdoor applications is toughness. Impact modifiers used to improve the toughness of PVC in outdoor use are CPE, EVA copolymers, and acrylates.The all‐acrylic weatherable impact modifier is designed especially to modify PVC for outdoor use and ease of processability. We will review its key performance features with special emphasis on the processing advantages of the all‐acrylic impact modifier. The study of the influence of processing conditions on the physical performance of weatherable PVC compounds in a Ba/Cd stabilized window profile shows an acrylic modifier to give consistently high toughness over a wide temperature range and shearing friction.