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2012, Volume 26 Issue 11 Publication date: 26 November 2012 Previous Issue Next Issue

Research Progress in Synthesis of Hydroxyl Functionalized Polyester

2012, 26 (11): 1-7 ; DOI: 10.19491/j.issn.1001-9278.2012.11.001

Abstract ( 1107 )

Several synthetic routes of hydroxyl functionalized polyester, including linear polycondensation, ringopening polymerization, hydroxyl group protection and deprotection, introducing hydroxyl group into the side chain of polyester and enzymatic polymerization, were introduced. The characteristics of every synthetic route were compared. Taking synthetic route by linear polycondensation, raw materials are rich and cheap, but reaction conditions are harsh. Taking synthetic route by ringopening polymerization, reaction time is short and performances of product are good, but cost of separating and recovering is high. Taking synthetic route by hydroxyl group protection and deprotection, experimental procedure is complex and yield of product is low. Taking synthetic route by introducing hydroxyl group into side chain of polyester, preparation of raw materials is not easy, so cost of the products is high. Taking synthetic route by enzymatic polymerization, reaction conditions are mild, but lipase is expensive and cost of the products is high.

Research Progress in PLA/Inorganic Nonacomposite Prepared by Insitu Technology

2012, 26 (11): 8-13 ; DOI: 10.19491/j.issn.1001-9278.2012.11.002

Abstract ( 1139 )

The research progress in nanocomposites of poly(lactic acid) and inorganic nanofillers was reviewed in this paper, with technologies of insitu polymerization and insitu precipitation being emphasized．These insitu methods overcame the problem of aggregation of the nanoparticles．The inorganic nanofiller was finely dispersed in and strongly interacted with the polymer matrix so that improved the thermostability，glass transition，mechanical properties，optical performance of the composites．And it avoided thermal degradation by a fused．The application of the poly(lactic acid) based the composites was enlarged.

Research Progress in Modification of Lignin and Its Application in Plastics

付蒙 Fu Meng

2012, 26 (11): 14-23 ; DOI: 10.19491/j.issn.1001-9278.2012.11.003

Abstract ( 1786 )

In this article the latest lignin modification research of insitu compatibilizing technology and chemical modification:sulfonation, oxidation, phenol chemical, hydroxylation, amination, graft copolymerization modification were reviewed;Reseach progress in application of the lignin in thermoplastic plastics such as polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), and thermosetting plastics such as phenolic resin (PF),epoxy resin, urea formaldehyde resin (UF), polyurethane (PU) was introduced. The existing problems and development trend of the technology also were analyzed.

Study on Rheological Behavior of APAO Hotmelt Pressure Sensitive Adhesive

2012, 26 (11): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2012.11.004

Abstract ( 1355 )

The influence of tackifying resin and plasticizer on the rheological behavior of atactic polymerized alpha olefin (APAO) based hotmelt pressure sensitive adhesive was investigated by means of an Advanced Rheology Expansion System (ARES). It indicated that the shear viscosity of the adhesive increased with increasing molecular weight of APAO. With the increase of C5 petroleum resin content, the shear viscosity achieved a peak value. The smaller the molecular weight of plasticizer was, the smaller the shear viscosity was, but there was no influence on the shear sensitivity with different plasticizers. APAO hotmelt pressure sensitive adhesive had a strong temperature sensitivity. The shear sensitivity increased as shear rate enhanced or temperature decreased.

Study on Sealant Used in Polyurethane Elastomer Prepared by Nonisocyanate Prepolymer Chain Extender

2012, 26 (11): 28-31 ; DOI: 10.19491/j.issn.1001-9278.2012.11.005

Abstract ( 1225 )

Polyether polyurethane prepolymer was capped with either methyl ethyl ketoxime and phenol, subsequently was chain extended with nonisocyanate polyurethane prepolymer, which was used to prepare the membrane. The capping and decapping temperatures of methyl ethyl ketoxime and phenol, as well as their capping effect were compared. Differential scanning calorimetry determined the capping reaction temperatures of methyl ethyl ketoxime and phenol were 100 ℃ and 80 ℃ respectively. Considering the capping effect, mechanical properties of the membrane, and environmental protection, methyl ethyl ketoxime was preferred to phenol. For the membrane based on methyl ethyl ketoxime, the tensile strength was 25.1 MPa, the elongation at break was 424 %. Thermogravimetric analysis indicated that the thermal properties of the membranes were not influenced by the capping agent.

Preparation of Acrylonitrile Grafted Polypropylene by Solid Phase Grafting Aided with Supercritical Carbon Dioxide

WANG Ya Zhen JIA Wei Nan

2012, 26 (11): 32-34 ; DOI: 10.19491/j.issn.1001-9278.2012.11.006

Abstract ( 1542 )

Dicumyl peroxide was used as an initiator in the reaction of grafting PP onto AN in a medium of supercritical carbon dioxide. IR was used to characterize the polymer. When the reaction temperature was 140 ℃,reaction time was 5 h, and AN content was 30 %，the grafting rate was 18.45 %, which was better than solution method.

Effect of APP on Flame Retardancy and Mechanical Properties of ABS Resins

Ge Yan-Xia Yang Jingwei

2012, 26 (11): 35-38 ; DOI: 10.19491/j.issn.1001-9278.2012.11.007

Abstract ( 1319 )

The effects of loading of ammonium polyphosphate (APP) and pentaerythritol（PER）, and their weight ratio on the mechanical and retardant properties of ABS were studied. The same effects of toughening agents of polysioxane and MBS were also studied. It showed that APP and PER had excellent synergistic effects on the flame retardancy of ABS. When the weight ratio of APP to PER was 3∶1 and the content of flame retardants exceeded 30 phr, a grade of UL94 V0 was achieved. The content of flame retardants had moderate effect on mechanical properties. When polysioxane or MBS was added to ABS together with 30 phr flame retardant, the impact strength slightly increased and retardant properties were seriously decreased.

Study on Solventless Epoxy/Imide/Anhydride Impregnated Resins

2012, 26 (11): 39-43 ; DOI: 10.19491/j.issn.1001-9278.2012.11.008

Abstract ( 1079 )

An epoxy resin was chain extended with carboxylcontaining imide, mixed with MeTHPA, an epoxy/imide/anhydride solventless impregnating resin was prepared. The curing technology of the resin was determined using differential scanning calorimetry and the heat resistance of the resin was characterized using thermogravimetric analysis. The storage stability was evaluated through the viscosity change after stored 96 hours at 60 ℃. It was found that anhydride improved the processability and storage stability, and imide enhanced the heat stability.

Preparation of Polylactide/Talc Composites by Insitu Polymerization

2012, 26 (11): 44-49 ; DOI: 10.19491/j.issn.1001-9278.2012.11.009

Abstract ( 1141 )

Polylactide/talc composites were prepared through in situ polymerization using silane coupling agent modified talcum powder（Talc）, which was characterized using Fourier transform infrared spectroscopy (FTIR)，scanning electronic microscope (SEM)，nuclear magnetic resonance (NMR)，thermo gravimetric (TG)，and polarizing optical microscope (POM). It showed that talc particles were dispersed uniformly in the matrix.The tensile and impact strengths of the PLA/Talc composites with 3 % talc were improved by 102.56 % and 47.83 %, respectively，compared with pure PLA. The thermal stability of the composites was improved visibly. Talc accelerates crystallization of PLA. Meanwhile, the degradation rate of composites was markedly accelerated.

Study on Ultrahigh Molecular Weight Polyethylene Composites Reinforced with Inorganic Fillers

xiaoyun qi

2012, 26 (11): 50-55 ; DOI: 10.19491/j.issn.1001-9278.2012.11.010

Abstract ( 1203 )

PEUHMW reinforced by wollastonite and ultrafine muscovite was researched, and then the composites were extruded by single screw extruder. Effect of different fillers on properties of the composites was studied, including mechanical properties, heat resistance, wear resistance, and so on. It showed that the tensile strength, surface hardness, heat distortion temperature and wear resistance could be improved with a proper content of fillers. Among two fillers, ultrafine muscovite was the best. With adding 5 % ultrafine muscovite, the tensile strength of the composite was increased by 28.7 %, heat distortion temperature was increased for 16 ℃ and wear rate was reduced by 58.3 %. With adding 15 % ultrafine muscovite, the coefficient of friction was reduced by 26.8%.

Nonisothermal Crystallization Kinetics of PE-LLD/NanoCaCO₃ Composites

GAO Jun-Gang

2012, 26 (11): 56-61 ; DOI: 10.19491/j.issn.1001-9278.2012.11.011

Abstract ( 1164 )

The PELLD/nanoCaCO3 composites were prepared through melting mixing using a tworoll plasticator. Nonisothermal crystallization behaviors of neat PELLD and the composites were studied by means of differential scanning calorimetry. Jeziorny and Mo methods were used to analyze the data. It showed that both Jeziorny and Mo methods could describe this system very well. According to the Jeziorny method, nanoCaCO3 increased the value of To. At the same time, the values of (To-Tp) and t1/2 also increased. This meant that the crystallization rate of PELLD was faster than that of PELLD/nanoCaCO3. For a given cooling rate, with increase of the content of nanoCaCO3, the value of crystallization rate decreased at first, then increased. When the content of nanoCaCO3 was 10 %, the value of crystallization rate was the lowest. The value of n changed from 1.47 to 2.13. The conclusion of Mo′s was the same as that of Jeziorny′s. The value of b changed from 0.75 to 1.22.

Study on Melt Modification of Polypropylene with Triallylisocyanurate

Peng CHEN

2012, 26 (11): 62-67 ; DOI: 10.19491/j.issn.1001-9278.2012.11.012

Abstract ( 1244 )

Polypropylene (PP) was melt grafted with triallyl isocyanurate (TAIC) through extrusion in presence of initiators DCP and BPO. Structure and thermal properties of modified PP were characterized using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry(DSC),and the gel rate was also determinated.The result showed that TAIC was successfully grafted onto PP backbone, increased the gel content and decreased the melt flow index. When the loading of TAIC was 5 phr, the gel content reached a maximum of 30.83 %, meanwhile the melt flow rate dropped to a minimum of 1.09 g/10 min. Compared with virgin PP, modified PP had higher crystalline temperature and higher melting temperature.

Effect of Nucleating Agent with High Relative Molecular Mass on Crystallization Behavior of Polypropylene

2012, 26 (11): 68-73 ; DOI: 10.19491/j.issn.1001-9278.2012.11.013

Abstract ( 1252 )

Crystallization behavior and morphology of polypropylene（PP） modified by high relative molecular mass nucleating agent（PNA） were researched by differential scanning calorimetry calorimeter and polarizing microscope. It showed that crystallization temperature (Tc) and crystallization peak temperature (Tp) of modified PP increased significantly.Tc and Tp of modified PP were 131.90 ℃ and 128.32 ℃ after adding 0.7 phr PNA, and the degree of crystallinity increased from 56.32 % to 61.63 %. The nucleation rate and size distribution were best when the content of PNA was 0.7 phr. PNA can promote the crystallization of PP, improve mold temperature of PP products, and shorten the production cycle of products.

Simulation Study on Effect of Injection Molding Processing Parameters on Birefringence of Transparent Products

2012, 26 (11): 74-78 ; DOI: 10.19491/j.issn.1001-9278.2012.11.014

Abstract ( 1096 )

The influence of different processing parameters on the average birefringence was simulated using Moldflow software. The optimized parameter of each factor′s contribution to the average birefringence was studied with orthogonal experimental method, and then the single factor experimental method was utilized to study the effect of different processing parameters on the average birefringence of the part. It showed that holding time and melt temperature contributed the most to the average birefringence, but the influence mechanism of them to the average birefringence was different. The holding time had a significant effect on birefringence only near the gate, while the melt temperature had an effect on birefringence in the whole area.

Hybrid Optimization of Processing Parameters of Injection Molding Based on Response Surface Model

2012, 26 (11): 79-82 ; DOI: 10.19491/j.issn.1001-9278.2012.11.015

Abstract ( 1181 )

The car reflectors were taken as an object of analysis, mold temperature, melt temperature, pack pressure as well as pack time were selected as the test variables, with the volume shrinkage rate and warpage as the optimum goal. The second order response surface model which described the relationship between test variables and optimum goal was established by BoxBehnken design method. Optimal sequences were found out after the variance analysis by using the DesignExpert software, and the optimal results were forecasted by the optimal sequences. Based on the optimal sequences, accuracy of model could be verified by the simulation analysis with Moldflow. The results demonstrated that optimization adopting response surface model was an effective way of improving quality of products.

Study on Rheological Behavior of NEP Type Ultra Bright Polyester

SHENG Ping-Hou Xin Luo Yun DING

2012, 26 (11): 83-87 ; DOI: 10.19491/j.issn.1001-9278.2012.11.016

Abstract ( 1139 )

Rheological behavior of NEP type ultra bright polyester and common ultra bright PET was investigated by means of a capillary rheometer. It showed that both NEP type polyester and common ultra bright PET melt were pseudoplastic.The viscous activation energy of NEP type polyester was lower than that of common ultra bright PET. The effect of temperature on the melt viscosity of ultra bright PET was more sensitive than that of NEP type polyester. NEP type polyesters was more similar to Newton fluids than common ultra bright PET at low shear rates .The nonNewtonian index at high shear rates of NEP type polyester was greater than common ultra bright PET. The nonNewtonian index at high shear rates of ultra bright PET enhanced more than that of NEP type polyester with the increase of temperature.

Numerical Study on Heating Phase of Rotational Molding

2012, 26 (11): 88-92 ; DOI: 10.19491/j.issn.1001-9278.2012.11.017

Abstract ( 1130 )

A new flow and heat transfer theoretical model was established for heating phase of rotational molding process for spherical hollow plastic parts, and numerical computation was performed by means of Fluent software based on the model. Heat conduction of mold, heat conduction of plastic layer and following melting, and convective heat transfer of internal air were coupled for the solution of the model. Heating time, temperature at outer wall of mold and temperature of internal air obtained by numerical computation were in good agreement with those by experiment, and thus the theoretical model was validated. In addition, heating time under different outer heating temperatures, outer convective heat transfer coefficients, and plastic layer thicknesses were calculated so that effects of these parameters on heating time can be determined. And some conclusions were made, such as increasing outer convective heat transfer coefficient could shorten heating time more effectively than raising outer heating temperature.

Study on Synthesis of Novel Phosphoruscontaining Epoxy Resin Prepolymer and Its Curing Process

2012, 26 (11): 93-96 ; DOI: 10.19491/j.issn.1001-9278.2012.11.018

Abstract ( 1254 )

Through the reaction in a system of 2methy2,5dioxo1,2oxaphospholane(OP)/mdihydroxybenzene/epoxy resin, a prepolymer was obtained. This phosphoruscontaining epoxy resin prepolymer could be selfcured. The product had good flame retardant properties. The limited oxygen index of cured epoxy resin was 25.0 %，vertical combustion test reach UL94 V0 level.

Preparation of OA Modified NanoMg(OH)₂ and Its Effect on Flame Retardancy of PE-HD

2012, 26 (11): 97-100 ; DOI: 10.19491/j.issn.1001-9278.2012.11.019

Abstract ( 1107 )

Using a method of direct precipitation, nano magnesium hydroxide (nanoMH) was prepared and modified with oleic acid (OA). The structure and morphology of the nanoMH powders were characterized using contact angle measuring instrument, XRD, TEM, FTIR, and TGDSC．It showed that OA was adsorbed on the surface of nanoMH powders and effectively decreases its surface energies, and hence greatly increased the contact angle. The nanoMH was introduced into PEHD forming a composite through pressing molding. It was found that the limited oxygen index was greatly enhanced by oleic acid treating, the limiting oxygen index increased from 16.8 % to 21.5 % when the nanoMH content was 15 %．

Application of Static Thermal Stability Experiment in Selection of Ca/Zn Thermal Stabilizer for PVC Transparent Hard Products

Shifa Yu Xin Qian

2012, 26 (11): 101-106 ; DOI: 10.19491/j.issn.1001-9278.2012.11.020

Abstract ( 1293 )

The thermal stabilizing function of Ca/Zn system in transparent rigid PVC products was compared with organic tin. It was found that the 194# Ca/Zn stabilizer had the best overall performance, the stabilization time was comparable with organic tin. For the weightloss property, the flaky stabilizer was poorer than, and the powder stabilizer was comparable to organic tin. The 194# Ca/Zn stabilizer resulted in higher transparency and lighter discoloration, which met the requirements for transparent rigid PVC products.

Determination of Gas Transmission of Plastic Wrap by Small Range Differentialpressure Instrument

Liu Shansheng wei Yuan

2012, 26 (11): 107-109 ; DOI: 10.19491/j.issn.1001-9278.2012.11.021

Abstract ( 1201 )

The instrument′s detecting range was not accurate enough for detecting the gastransmission of single layer of plastic wrap when using differentialpressure method to detect the gastransmission. We detected the gastransmission of multilayer plastic wrap and found a relationship of the gastransmission and the layers of plastic wrap. Thus we could get accurate test results and expand the detection range of the instrument by use the relationship.

Design Development for Double Position Plastics Extrusion Hollow Blow Molding Machine

WU Yunong

2012, 26 (11): 110-113 ; DOI: 10.19491/j.issn.1001-9278.2012.11.022

Abstract ( 1585 )

In order to make the doubleposition extrusion hollow blow molding more smoothly with more accurate location and easier operation, the buffer hydrocylinder, hydraulic circuit, bottle blow control method, and the air blow equipment were improved. After the improvement was accomplished, the safety, production efficiency, and product qualification rate of the machine was greatly increased.