Acrylic Impact Modifier Research Articles

Novel high-efficiency Poly(butyl acrylate-co-2-ethylhexyl acrylate) grafting of Poly(methyl methacrylate) impact modifier: Synthesis and application

Polyacrylate latexes with uniform particle size and excellent dispersion were successfully synthesized via emulsion copolymerization of butyl acrylate and 2-ethylhexyl acrylate with different types of grafting agents. The effect of grafting agent type for residual double bonds of seed latex was discussed. The results indicated that the residue double bonds of acrylic seed latex of graft agents with non-equally active double bonds were higher than acrylic seed latex of graft agents with equally active double bonds. Acrylic impact modifiers (ACR) were generated by using an emulsion grafting polymerization of polyacrylate latex as the core and poly (methyl methacrylate) (PMMA) as the shell for preparing poly(vinyl chlorid) (PVC)/ACR blends. Mechanical properties test analysis shows that the PVC/ACR blend reached a brittle-toughness transition when the ACR content was 8 phr, indicating that modifiers play a good toughening role in the matrix. The highest impact strength of PVC toughened through ACR (dicyclopentenyl acrylate as grafting agent) was 1682 J/m, almost 62 times than the pure PVC, whereas only 45 times than the pure PVC that of traditional ACR prepared PVC/ACR blend. Scanning electron microscope graphs showed that the shear yielding of the matrix was the major toughening mechanisms.

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.

Film Performance of Poly(lactic acid) Blends for Packaging Applications

Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. PLA based films for food packaging has been an area of both commercial and research interest within the context of sustainability. In spite of its high strength, packaging applications have been limited because PLA is more brittle than traditional oil-based plastics. Because of this, films display low tear and impact resistance and produce a loud crackling sound when manipulated. Although many studies address the toughening of PLA in the bulk, little attention has been placed on the film performance. The present study is aimed at providing a survey of binary PLA based blends with other biodegradable and non-biodegradable plastics. Acrylic impact modifier (AIM, 5 wt. %), ethylene vinyl acetate (EVA, 20 wt.%), polyhydroxyalkanoate (PHA, 10 wt.%), polycaprolactone (PCL, 30 wt.%), polybutylene succinate (PBS, 20 wt.%) and polypropylene carbonate (PPC, 30 wt.%) were each blended with PLA through single-screw extrusion and converted into films via the blown-film process. Tear and impact resistance, heat seal strength, and noise level were measured. EVA, PHA, PCL, and PBS improved the tear resistance with EVA having the highest effect (>2x). Similarly AIM, EVA and PPC improved the resistance of the film to impact-puncture penetration. Heat seal strength was significantly improved by the PHA and moderately increased by AIM (2x) and EVA. Additionally, we proposed a method to quantify the annoyance of the noise made by the films upon manipulation. PCL and PBS significantly reduced the annoyance level of the films.

Effect of matrix chain entanglement on toughening mechanism evolution of acrylic impact modifier toughened methyl methacrylate-N-phenylmaleimide copolymers

The toughening mechanism evolution of acrylic impact modifier (AIM) toughened methyl methacrylate-N-phenylmaleimide copolymers (PMMA-PMI) was investigated in terms of matrix chain entanglement density (νe), especially within the range of matrix νe ≈ 0.1 mmol/cm3. After respectively blended the PMMA-PMI having designed νe with the same content preformed AIM, it was showed that the notched impact strength of the blends increase with PMMA-PMI νe enhancement. The morphological analyses revealed that the extent of shear yielding gradually enlarged when matrix νe is higher than 0.1061 mmol/cm3. Whereas, in the AIM/PMMA-PMI blend with lower matrix νe, the toughening mechanism transformed into matrix crazing triggered by PBA cavitation. The results suggest that the response of the matrix with different νe to the rubber particle cavitation dominate toughening mechanism and mechanical performance of AIM/PMMA-PMI blends, and it is believed that matrix νe is an inherent factor to toughening mechanism evolution.

The Effect of Core–Shell Ratio of Acrylic Impact Modifier on Toughening PLA

ABSTRACTAcrylic impact modifier (ACR), one kind of methyl methacrylate–butyl acrylate copolymer with a core–shell structure, was prepared by seed emulsion polymerization. The weight ratio of core–shell ranges from 85.5/14.5 to 71.9/28.1. Then PLA/ACR blends were prepared with a constant ratio of 80/20. The effect of core–shell ratio of ACR on toughening PLA was investigated. Torque analysis revealed that the torque values of PLA/ACR blends increased with increasing shell content of ACR. The impact strength of PLA/ACR blends reached the highest value of 77.1 kJ m−2 when the core–shell ratio of ACR was 79.2/20.8. Transmission electron microscope (TEM) photographs revealed that ACR was dispersed uniformly in the PLA matrix. Scanning electron microscopy (SEM) suggested that the plastic deformation and cavitations were the major toughening mechanism for the PLA/ACR blends. The shell partition PMMA of ACR was partially miscible with PLA from dynamic mechanical analysis.

High‐efficiency impact modifier prepared by coagulation emulsion polymerization through internal voiding toughening mechanism

This paper was an application of our previous study on particle coagulation mechanism (Colloid Polym Sci 291: 2385‐2398, 2013), and the effect of coagulation particle of acrylic impact modifiers (ACR) on polymer blend properties was investigated. The compatibility was relevant with the properties of shell phase rather than the structure of core phase. The rubber content was found to be the main influencing factor for toughening when rubber content less than 5%. However, when it reached to 7%, the dispersion of rubber became the primary parameter to dominate the toughness. The highest impact strength of poly(vinyl chloride) (PVC) toughened by coagulation particles was 1656 J/m, nearly 56 times than pure PVC, whereas only 45 times was reached when toughening by traditional ACR prepared by seeded emulsion polymerization; moreover, the brittle–ductile transition happened in advanced of 2 phr at ACR content. Scanning electron microscopy results showed that the shear yielding of the matrix and rubber cavitation were the major toughening mechanisms. Furthermore, the high performance of blend responsible for coagulation particles was discussed. Copyright © 2014 John Wiley & Sons, Ltd.

Arkema introduces new PVC impact modifier; doubles Chinese peroxide capacity

In the USA, Arkema Inc has extended its Durastrength® impact modifier family with the introduction of a new high-rubber product. According to the company, Durastrength 350 is a high-efficiency acrylic impact modifier designed to provide ‘exceptional toughness’ to weatherable PVC applications. Elsewhere, parent company Arkema is building a new plant for the production of organic peroxides at its Changshu site in China.

Study on Tough Blends of Polylactide and Acrylic Impact Modifier

Acrylic impact modifiers (ACRs) with different soft/hard monomer ratios (mass ratios) were prepared by semi-continuous seed emulsion copolymerization using the soft monomer butyl acrylate and the hard monomer methyl methacrylate, which were used to toughen polylactide (PLA). The effect of soft/hard ACR monomer ratio on the mechanical properties of PLA/ACR blends was investigated. The results showed that the impact strength and the elongation at break of PLA/ACR blends increased with increasing soft/hard ACR monomer ratio, while the tensile and flexural strengths of PLA had little change. The impact strength of PLA/ACR blends could be increased about 4 times more than that of pure PLA when the soft/hard monomer ratio of ACR was 90/10, which was the optimal ratio for good mechanical properties of PLA. Additionally, the possible mechanism of ACR toughening in PLA was discussed through impact fracture phase morphology analysis.

Influence of acrylic impact modifier on plasticized polylactide blown films

Polylactide (pla) was first plasticized with polydiethylene glycol adipate (pdega). then the plasticized pla was further blended with acrylic impact modifier (acr) using a twin-screw extruder. finally, the extruded samples were blown using the blown thin film technique. both pdega and acr significantly affected the physical properties of the films. the results indicated that elongation at break and the tear strength of the films were significantly improved. the cavitation and large plastic deformation observed in films subjected to the tear test were the important energy-dissipation process, which led to a torn pla film. moreover, the pla/pdega/acr blown films had excellent optical properties. acr could act as a tear resistance modifier for pla blown films. these findings contribute new knowledge to the additives area and give important implications for designing and manufacturing polymer packaging materials. (c) 2013 society of chemical industry

Synthesis of montmorillonite-modified acrylic impact modifiers and toughening of poly(vinyl chloride)

A series of Na-montmorillonite (Na+-MMT) modified acrylic impact modifiers (mAIM) were prepared by seeded emulsion polymerization. These mAIM modifiers were characterized by XRD. A 0.24 nm of increased interlayer distance of Na+-MMT was an indication of polymer chains intercalation within interlayer spacing. The notched Izod impact tests proved that the impact strength of the PVC/AIM composites prepared by melt blending was 43 J/m, markedly higher than the impact strength of pure PVC. Furthermore, with increasing content of AIM, the composites exhibited changes from brittle fracture to ductile fracture, with the impact strength increasing from 200 to about 1,000 J/m. The impact strength of PVC/mAIM also showed the same trend, although there were drops in some values. The impact strength of PVC/mAIM composites decreased with the increases in Na+-MMT content, but the yield strength and modulus of the composites increased with higher Na+-MMT content. The result also showed that the tensile strength of mAIM with 2 wt % Na+-MMT is lower than that of mAIM with 0.8 and 1 wt % contents, but still sufficiently large in comparison to the tensile strength of mAIM with 0 wt % Na+-MMT. The dynamic mechanical analysis (DMA) result showed that the glass transition temperature (T g) of mAIM did not show obvious changes and the elasticity of mAIM was reduced with the additional Na+-MMT content.

Flexural and Impact Properties of Poly (Vinyl Chloride) and Acrylic-Impact Modified Poly (Vinyl Chloride) Composite Filled with Poly (Methyl Methacrylate) Grafted to Oil Palm Empty Fruit Bunches

Effects of oil palm empty fruit bunch (OPEFB) fiber and OPEFB grafted with poly (methyl methacrylate) on mechanical properties of poly (vinyl chloride) (PVC) and acrylic-impact modified PVC were investigated. The formulations were blended into sheets on a two-roll mill. Test specimens were then hot-pressed. The flexural strength increased, the flexural modulus decreased, and the impact strength relatively constant with the incorporation of grafted fiber. The impact strength of grafted composite improved after acrylic impact modifier (AIM) was added into the grafted composite matrix compared to ungrafted and grafted composite without AIM. The flexural strength and modulus of grafted composite decreased with the addition of AIM.

Preparation of a structured acrylic impact modifier and its application in toughening polyamide 6

AbstractA series of poly(n‐butyl acrylate)/poly(methyl methacrylate‐co‐acrylic acid), i.e., poly(BA/MMA‐co‐AA), core‐shell structured modifiers with different contents of crosslinking agent allyl methacrylate and functional monomer were prepared, and its effects on mechanical properties of polyamide 6 (PA 6) blends were investigated. The modifiers were prepared at a solid content of 50 wt% by a seeded emulsion polymerization. Dynamic light scattering measurement showed that the particle grew without significant secondary nucleation occurring. The morphology was confirmed by means of transmission electron microscopy. Scanning electron microscopy was used to observe the morphology of the fractured surfaces. The dynamic mechanical analysis measurements indicated that the appearance of two merged transition peaks and the magnitude of the loss peak of PA 6 matrix with the addition of PBMA core‐shell modifier in the PA 6/PBMA blends were responsible for the improvement of PA 6 toughness. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

Mechanical Properties and Morphology of Polylactide Composites with Acrylic Impact Modifier

Polylactide (PLA) composites with acrylic impact modifier BPM, i.e., PLA/BPM composites, were produced by the melt blending method. The effects of BPM on the thermal properties, melting behaviors, and dynamic mechanical properties of the PLA/BPMs were investigated by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Tensile strength, flexural strength, and modulus of the injection molded specimens were measured by an Instron tensile machine. The influence of BPM on the impact strength of injection molded PLA/BPM composites was examined using an impact tester. The morphology of cryofractured surfaces and fracture surfaces of the composites after the tensile and impact testing was also investigated using scanning electron microscope. The test results show that the composites with BPM possess better flexibility when compared with neat PLA. However, the notched Izod impact strength showed improvement only when the BPM content was higher than 15 wt%.

Effect of nanocalcium carbonate on the impact strength and accelerated weatherability of rigid poly(vinyl chloride)/acrylic impact modifier

AbstractPoly(vinyl chloride) (PVC) composites filled with nano‐ and micro‐CaCO3 particles were prepared via a melt blending method. Transmission electron microscopy images revealed better dispersion of nano‐CaCO3 than micro‐CaCO3 in the PVC matrix. With more than 5 phr (parts per 100 parts of resin) of nano‐CaCO3 content, both impact strength and heat stability were improved. Accelerated weathering tests were performed to investigate UV stability. The impact strength and white index obtained upon weathering exposure of PVC/(80 μm CaCO3) nanocomposites showed a significant improvement upon incorporating nano‐CaCO3. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers

Mechanical Properties of Unplasticised PVC (PVC-U) Containing Rice Husk and an Impact Modifier

The objective of this study was to investigate the effects of rice husk and acrylic impact modifiers on the mechanical properties of unplasticised poly(vinyl chloride) (PVC-U) composites. The composites were prepared using a two-roll mill at temperature 165 °C before being hot pressed at 185 °C. The incorporation of rice husk (RH) fillers from 10 to 40 per hundred resin (phr) has increased the flexural and tensile modulus of the unmodified and modified (8 phr impact modifier) PVC-U composite. The flexural strength for both unmodified and modified PVC-U composite was observed to increase until RH loading of 20 phr. However, the tensile and impact strength of PVC-U composite decreased with RH loading. The scanning electron microscopy (SEM) showed that the rice husk fillers agglomerated and unevenly distributed throughout the matrix. The result showed that the impact strength of the filled PVC-U composites (20 phr filler) increased but the tensile and flexural properties decreased with increasing impact modifier content. The formulation containing 8 phr of acrylic impact modifier and 20 phr of RH loading showed the best balance of stiffness and toughness properties.

Comparative study of the effects of chlorinated polyethylene and acrylic impact modifier on the thermal degradation of poly(vinyl chloride) compounds and poly(vinyl chloride)/(oil palm empty fruit bunch) composites

AbstractThe effects of chlorinated polyethylene (CPE) and acrylic impact modifier (AIM) on the thermal degradation of poly(vinyl chloride) (PVC) compounds and composites were investigated. The amounts of AIM and CPE used were fixed at 9 parts per hundred parts of resin (phr), while oil palm empty fruit bunch (OPEFB) fiber content was increased from 0 to 40 phr. To produce composites, the PVC formulations were dry‐blended by using a laboratory blender before being milled into sheets on a two‐roll mill at 165°C. The milled sheets were then hot‐pressed at 180°C. The thermal degradation of the specimens was evaluated by using thermogravimetry in a nitrogen environment. Thermal stability of the PVC/CPE compounds and PVC/CPE/OPEFB composites was improved by the addition of CPE. The CPE retarded the dehydrochlorination of PVC. However, the stabilization effect was reduced by the incorporation of OPEFB at levels of 30 and 40 phr. The presence of AIM accelerated the dehydrochlorination of PVC/AIM compounds and PVC/AIM/OPEFB composites. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers

Influence of the rubber crosslinking density of a core–shell structure modifier on the properties of toughened poly(methyl methacrylate)

AbstractFour kinds of core–shell structure acrylic impact modifiers (AIMs) with different rubber crosslinking densities were synthesized. The effects of the rubber crosslinking density of the AIMs on the crack initiation and propagation resistance and the mechanical properties of the AIM/poly(methyl methacrylate) (PMMA) blends were investigated, and we found that the maximum stress intensity factor, crack propagation energy, and Izod impact strength reached maximums when the appropriate rubber crosslinking density of AIM, 2.51 × 1025 crosslinks/m3, was adopted. Transmission electron microscopy photographs of the AIM/PMMA blends showed that the AIMs dispersed uniformly in the PMMA matrix. Meanwhile, through the analysis of optical photos and scanning electron microscopy of the impact fracture surface, we found that the deformation mechanism of the AIM/PMMA blends was local matrix shear yielding initiated by rubber particle cavitation of the AIM. The rubber of the AIM, whose crosslinking density was 2.51 × 1025 crosslinks/m3, was beneficial to the formation of intensive voids and initiated the local shear yielding of nearby modifiers of the PMMA matrix effectively in impact tests, which led to higher Izod impact strengths. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Study of processability of poly(vinyl chloride): Effects of acrylic and chlorinated polyethylene impact modifiers, oil palm empty fruit bunch fiber, and mixing temperature

AbstractThe influence of acrylic impact modifier, chlorinated polyethylene (CPE) impact modifier, oil palm empty fruit bunch (OPEFB) fiber, and mixing temperature on the processability of poly(vinyl chloride) (PVC) compounds was investigated. The acrylic impact modifier was the most efficient additive in reducing the fusion time of the PVC, followed by the OPEFB fiber and the CPE impact modifier, whereas OPEFB was the most efficient in decreasing the melt viscosity of the compounds, followed by CPE and acrylic. A PVC compound containing 9 phr of CPE and 40 phr of OPEFB had high values of fusion time and end torque. The fusion time and melt viscosity of all of the PVC compounds decreased with increasing mixing temperature. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.

Independence of the brittle–ductile transition from the rubber particle size for impact‐modified poly(vinyl chloride)

AbstractA series of acrylic impact modifiers (AIMs) with different particle sizes ranging from 55.2 to 927.0 nm were synthesized by seeded emulsion polymerization, and the effect of the particle size on the brittle–ductile transition of impact‐modified poly(vinyl chloride) (PVC) was investigated. For each AIM, a series of PVC/AIM blends with compositions of 6, 8, 10, 12, and 15 phr AIM in 100 phr PVC were prepared, and the Izod impact strengths of these blends were tested at 23 °C. For AIMs with particle sizes of 55.2, 59.8, 125.2, 243.2, and 341.1 nm, the blends fractured in the brittle mode when the concentration of AIM was lower than 10 phr, whereas the blends showed ductile fracture when the AIM concentration reached 10 phr. It was concluded that the brittle–ductile transition of the PVC/AIM blends was independent of the particle size in the range of 55.2–341.1 nm. When the particle size was greater than 341.1 nm, however, the brittle–ductile transition shifted to a higher AIM concentration with an increase in the particle size. Furthermore, the critical interparticle distance was found not to be the criterion of the brittle–ductile transition for the PVC/AIM blends. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 696–702, 2006

Effect of aging time on properties of acrylic impact modifier modified bisphenol A polycarbonate

AbstractPolycarbonate (PC) was blended with acrylic impact modifiers (AIMs). The effects of modifiers weight fraction on the Izod impact strength and yield strength of PC/AIM blends were investigated. The samples with 4% modifiers were aged under the Tg of PC in an air‐circulating oven, and the effects of aging time on impact strength, yield strength, modulus, elongation at break, post yield stress drop (PYSD) values, and morphology of fracture surface were investigated. The effects of aging time on the shape of stress–strain curve were also investigated. The aged samples were heat‐treated over the Tg of PC to erase the effects of physical aging. It was found that the drop of impact strength caused by physical aging can be recovered, the increment of yield strength and PYSD value caused by physical aging can only be partly recovered, and the heat‐treatment over the Tg of PC caused further increment of modulus. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2715–2724, 2005