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Lei Hu,Bin Yang,Yan-Li Deng,Fei-Xue Lu,Ru Xia,Zheng-Zhi Zheng,Ji-Bin Miao,Jia-Sheng Qian,Chuan-Ru Zhang,Peng Chen,Yu-Chuan Zhang 한국고분자학회 2017 폴리머 Vol.41 No.4
The effects of cooling medium temperatures and plastic/rubber ratios on solidification and crystallization kinetics of dynamically-vulcanized polypropylene/ethylene-propylene-diene rubber (PP/EPDM) blends were investigated with the aid of an in-situ measurement technique. The cooling medium temperature heavily influenced the solidification kinetics primarily due to a combination of latent heat liberated from the molten polymer and the heat transferred away via the metallic wall during the cooling period. Interestingly, the parameter C in three-parameter model was not only affected by the material properties, but also by the cooling condition, different from the previous literature. The crystallization kinetics analysis indicated that the effect of EPDM in the blends consisted of both nucleation-promoting effect (low EPDM loading) and steric effect (higher EPDM loading). The present kinetic analysis may be helpful to further studies on improving the product performances for industrial applications.
Thermal Tensile, and Dynamic Mechanical Properties of PVDF/FKM Blends in Different Curing Systems
Mojtaba Deilamy Moezzi,Mohammad Karrabi,Yousef Jahani 한국고분자학회 2017 폴리머 Vol.41 No.2
Blends of poly(vinylidene fluoride) (PVDF) and fluororubber (FKM) were prepared in an internal mixer by dynamic vulcanization. The effect of FKM, with and without curing system, was studied with respect to the properties of the PVDF/FKM blends. The tensile test showed that the tensile strength and modulus decreased after blending but the elongation-at-break naturally increased because of the presence of rubber in PVDF matrix. The differential scanning calorimetry (DSC) test gave good indications of improved state of miscibility in most blend ratios. The increase of FKM content showed a favorable tendency of PVDF component toward crystallization. The incorporation of FKM as a coblend improved the thermal stability of PVDF, and the temperature at 10% weight loss of the blends increased. This was confirmed by one value of glass transition temperature obtained from DMTA test, which indicated two different values for pure polymers. The rheological tests showed that the complex viscosity and storage modulus of the blends increased with increasing frequency.
Study on Crystallization Kinetics of Dynamically-Vulcanized PP/EPDM Blends
Bin Yang,Yan-Li Deng,Xia Ru,Ji-Bin Miao,Ming Cao,Jia-Sheng Qian,Li-Fen Su,Peng Chen,Jing-Wang Liu,La-Xia Wu,Tao Pang 한국고분자학회 2016 폴리머 Vol.40 No.4
Two types of β nucleating agents (β-NAs), aryl dicarboxylic acid amide (TMB-5) and diphenyl phthalate diamine (NT-C), were adopted to modify the polypropylene (PP)/ethylene propylene diene monomer (EPDM) blends, which were prepared by dynamic-vulcanization technology. Wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) were used to study the crystallization kinetics of PP. Our results showed that the addition of β-NAs can considerably increase the crystallization temperature, and significantly decrease the spherulite size of β-PP (L300). The Jeziorny analysis showed there were ~82% and ~89% of relative crystallinity generated from the primary crystallization in the composites containing TMB-5 and NT-C, respectively. The crystallization half time (t0.5) showed that NT-C improved the overall crystallization rate more effectively than TMB-5. In addition, the peaks of the relative crystallization rate curves were shifted towards higher temperature by 14 and 9℃ with the addition of TMB-5 and NT-C, respectively.
Dynamic DSC를 이용한 개질 고무 블랜드의 가황 반응에 관한 연구
안원술 ( An Won Sul ),이승현 ( Lee Seung Hyeon ) 한국고무학회 2003 엘라스토머 및 콤포지트 Vol.38 No.4
Dynamic DSC 방법을 이용하여 isoprene(IR) 및 chloroprene(CR) 고무로 개질된 NR/CB 고무 복합체의 가황반응을 연구하였다. 각각의 샘플에 대하여 승온속도를 달리한 열분석 곡선을 얻었고 이로부터 Kissinger의 해석 방법에 따라 가교반응 기구를 연구하였다. 실험에 사용된 고무 복합재료는 대개 120~180℃ 사시의 온도영역에서 가교 반응이 일어나는 것이 확인되었으며, 승온속도가 3℃/min에서 30℃/min로 빨라질수록 최대반응 속도점의 온도(T_(p))는 점점 높은쪽으로 이동하였고, 반응 발열량도 상대적으로 커지는 것으로 관찰되었다. Kissinger의 해석방법을 이용하여 실험 데이터를 분석한 결과, 실험에 사용된 샘플의 가교반응은 1차반응에 의해 진행되는 것으로 밝혀졌으며 개질제로서 사용된 고무 중에서 IR을 사용한 경우보다는 CR을 개질제로 사용한 경우에 반응온도에 상대적으로 더 민감한 것으로 판명되었다. 그러나 충전제로 사용된 카본블랙의 경우에는 종류와는 무관하게 반응기구에는 거의 영향을 미치지 않는 것으로 밝혀졌다. Even though many studies have been reported about rubber vulcanization, it is still remained difficult to find a quantitative relationship between the final states of vulcanized rubber and initial formulation or processing conditions. Dynamic differential scanning calorimetry (DSC) method is known as a comparatively easy method to research for the rubber vulcanization in both experimental and analysis. In the present research, a study on the vulcanization reaction of NR/CB composites modified by isoprene(IR) and chloroprene(CR) rubbers is carried out using dynamic DSC method. Thermograms with several different heating rates were obtained and analyzed using the Kissinger method. Analysis showed that the vulcanization reaction was progressed through the first order reaction mechanism. In addition, the reaction temperature was severely influenced by the kinds of rubber modifiers, in this case, more influenced by CR than by could hardly influence on the reaction mechanism.
권민호,이홍찬,이서휘,전흥배,오민철,Jeffrey Pyun,백현종 한국고분자학회 2020 Macromolecular Research Vol.28 No.11
Elemental sulfur (S8) is an inexpensive chemical feedstock for polymeric materials but has the disadvantages of poor solubility in organic media and inferior physical properties in the elemental form. We report on the preparation of organosulfur chalcogenide hybrid inorganic/organic polymer (CHIPs) based on bifunctional norbornene comonomers using dynamic covalent polymerization (DCP). A poly(sulfurrandom- styrene) (p(S-r-Sty)) resin was utilized to address the limited solubility/ miscibility of norbornene-containing comonomers in liquid sulfur. This report demonstrated the ability to expand the scope of organic comonomers to prepare organosulfur CHIPs from elemenatal sulfur using a combination of inverse vulcanization and dynamic covalent polymerization.
김수빈,장영욱 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
Dynamically vulcanized thermoplastic polyurethane(TPU)/silicone rubber(Q) blends were prepared in internal mixer using dicumyl peroxide as a curative and two-different type of coagents. Effects of silicone rubber content and dynamic vulcanization on surface morphology, wettability, and mechanical properties of the blends were characterized by water contact angle measurement, atomic force microscopy(AFM), and tensile test. Thermo-oxidative stability of the blend was examined using TGA, and the kinetic analysis was performed by using Kissinger method to obtain apparent activation energy and related parameters for the thermo-oxidative degradation.